Delta IXI: Deployable Structure with Flax Fibre Pultruded Profiles for Architectural Applications—Case Studies in Furniture and Adaptive Facade Systems

Abstract

Material selection is essential for advancing sustainability in construction. Biocomposites contribute significantly to raising the awareness of materials derived from biomass. This paper explores the design development and application of novel natural fibre pultruded biocomposite profiles in a deployable system. Development methods include geometrical studies to create a system that transforms from flat to three-dimensional. Physical and digital models were used to refine the geometry, while connection elements were designed to suit material properties and deployability requirements. The first case study, at a furniture scale, demonstrates the use of the profiles connected using threading methods to create a lightweight multifunctional deployable system enabling easy transport and storage. This system can be locked at various heights for different purposes. The realised structure weighs 4 kg, supporting weights up to 150 kg. The second case study applies the system architecturally in an adaptive kinetic facade, adjusting to the sun’s position for optimal shading, providing up to 70% daylight when open and as little as 20% when closed. These two structures validate the developed deployable system, showcasing the versatility of biocomposite profiles in such configurations. This approach enhances sustainability in architecture by enabling lightweight, adaptable, and eco-friendly building solutions.

1. Introduction

Materials are crucial in architecture, directly impacting design and construction outcomes. The construction industry accounts for around 40% of global carbon emissions, underscoring the need for sustainable practices [1]. With the EU’s Green Deal targeting a 60% emissions reduction by 2030 [2], alternative approaches are essential. Material selection is critical to lowering the carbon footprint, as commonly used building materials are significant contributors. Transitioning to sustainable materials can address this issue; selecting low-carbon options that are preferably locally sourced, biodegradable, or recycled can significantly reduce the environmental footprint.

Current research efforts at the BioMat department of the ITKE Institute at the University of Stuttgart have been investigating the application of biocomposite materials in architectural and structural systems. The Material and Structure seminar, focusing on the intersection of material research, design, and fabrication, has explored material properties to create innovative, lightweight designs through projects such as stools or mock-ups, serving as prototypes for larger architectural structures. The investigated topics include tailored fibre placement and 3D printing with natural fibres, various mouldless fabrication methods, growing materials, and shape memory biomaterials.

The significance of this topic is highlighted in various studies showcasing systems applied across different scales and thematic contexts. These works explore a diverse range of materials, including natural fibres such as flax and hemp, grown bio-materials like mycelium and its composites, and other polymeric composite systems. The fabrication techniques employed are equally varied, encompassing advanced composite manufacturing processes, traditional handcrafting methods, and emerging technologies like 3D printing, each contributing to the development of innovative material applications [3,4,5,6,7,8].

1.1. Biocomposite Profiles

As part of the LeichtPRO research project led by BioMat, a new biocomposite product has been created using pultrusion, a continuous process for manufacturing Fibre-Reinforced Polymers (FRP). This technique yields composites made of continuous fibres, resulting in unidirectional profiles with consistent cross-sections. The resulting profiles are of tubular geometry, measuring 25 mm in diameter with a 4 mm wall thickness, and can be produced in any length. They are made from natural flax fibre rovings reinforced with a customised plant-based matrix. Developed as structural elements for various applications, the biocomposite profiles have undergone mechanical testing, resulting in a compression strength of 31.2 kN and a flexural strength of 300 MPa [9,10]. For biocomposites, preventing material penetration and surface damage is essential to protect fibres from weathering, which can lead to moisture ingress and degradation. UV radiation and moisture can accelerate ageing, weakening the material over time [11]. As a result, connection methods for these biocomposites must focus on non-invasive techniques to ensure long-term durability and performance in various environments.

Initially engineered for active-bending structural applications, the developed profiles exhibited notable flexibility with a minimum bending radius of approximately 2.4 m. This was demonstrated in the first large-scale structural demonstrator to apply the material, the LightPRO Shell, a lightweight, biocomposite gridshell featuring a continuous outer perimeter beam, built at the University of Stuttgart in 2021. The structure spans 10 m and reaches 4.5 m at its highest point. While flexible in longer lengths, it exhibited remarkable compressive behaviour in shorter sections under 2 m, inspiring the exploration of additional applications. A 5 m span reciprocal canopy, featured at the ECC Venice Biennial 2023, and tensegrity configurations at different scales highlight potential applications for this new material. Additional prototypes, such as support structures and domes, have also been investigated for possible applications of the developed biocomposite profiles. All the described structures and developments have been examined in multiple scientific publications. A comprehensive overview of the developed lightweight structures and architectural applications of biocomposite natural fibre pultruded profiles is provided in [12]. Inspired by these segmented structures featuring shorter profiles led to an investigation into their potential applications in deployable configurations. This exploration aims to harness their unique properties for structures that can be easily assembled and disassembled, offering versatility and adaptability in various architectural contexts.

1.2. Deployable Structures

Deployable structures are adaptable systems designed to transition from a compact, stowed state to a fully expanded form when activated [13]. Their efficiency in storage and transport, combined with their lightweight and flexible nature, makes them ideal for temporary or portable applications. Deployable structures can be categorised based on the materials and the size of their components, with types including rigid components, such as bars or surfaces, and deformable or flexible elements or combinations of both [14,15]. Prominent examples of rigid deployable systems are the scissor structures, which use pin connections to create a scissor-like mechanism [16], latticework, and sliding mechanisms. Although the components are typically straight, linear, and rigid, some variations may differ. Surface deployable structures often feature foldable designs, where larger surfaces or plates bear the structural stresses instead of individual bar components, inspired by paper-folding techniques, such as origami [17]. Other deployable structures include inflatable and tensile systems, which achieve their final form through inflation or the tensioning of members. Tensile structures sometimes also incorporate deployability through membranes or cables. Additionally, hybrid systems, such as tensegrity structures, combine rigid bars and flexible cables, collapsing into a compact form and deploying by adjusting the tension in the cables [18,19,20,21,22].

There are several key design considerations when designing a deployable structure. First, classifying the structure into one of the previously mentioned typologies is essential to establish the foundational standards. The choice of mechanism is vital to ensure efficient transitions between states while maintaining stability and load-bearing capacity based on the geometric principles and intended application. Material selection is equally important, both geometrically and mechanically, to support the required loads and constraints, and it is a key factor for joint typology choices. Balancing these factors while managing complexity and maintaining cost efficiency is challenging. Connection elements are critical, as they must be selected to match the materials and load-bearing requirements. These connections influence the structure’s strength and durability, enabling it to withstand repeated use and dynamic forces, key factors depending on the intended application [15,23]. Geometric optimisation, combined with consideration of material properties and connection strategies, can significantly enhance the potential of deployable structures in architectural contexts [24].

The concept of transformable structures has roots in ancient architecture, where various movable systems were designed to meet specific needs, facilitate transformation, and enable relocation. Over time, this idea expanded from everyday-use elements, such as retractable roofs and foldable walls, to larger architectural systems. These early innovations laid the foundation for modern deployable structures [25]. These adaptable designs can respond to site conditions and user needs, offering flexible solutions that can be adjusted in real-time for functionality and mobility, demonstrating their versatility across various scales and contexts.

In architecture, deployable structures are commonly used in temporary or mobile solutions, such as event spaces, exhibitions, and emergency shelters. Their adaptable nature makes them suitable for flexible applications, such as adjustable shading elements, kinetic partitions, and deployable roofs [26]. Despite their widespread use, research on the integration of sustainable materials within deployable configurations into broader architectural applications remains limited. Current studies have primarily focused on the mechanical aspects of these systems [27,28], while limited solutions focus on sustainable materials without compromising functionality or adaptability. This manuscript addresses this challenge by investigating the use of novel biocomposite profiles in deployable structures, offering insights into how these materials can enhance both performance and environmental impact. By focusing on material as the key driver of design, this research merges material explorations with deployable structure design studies. This study aims to promote sustainable design practices in deployable structures, advancing sustainable practices and enhancing adaptability, scalability, and sustainability in various architectural contexts.

1.3. Scope of the Research

The scope of this research is to investigate the application of biocomposite pultruded profiles in deployable structures, focusing on scissor-like systems where the profiles serve as primary rigid components. The study explores geometric configurations that transition from a flat state for transportation to a three-dimensional structure with multiple locking positions. To validate the design, physical testing and experimentation were conducted to evaluate load-bearing capacity, deployment efficiency, and material performance. Two case studies were developed: a multifunctional furniture piece demonstrating the kinematic feasibility and practical deployment of the system and an adaptive parametric facade design. This research aims to demonstrate the potential of biocomposite profiles for lightweight, adaptable, and sustainable architectural solutions.

2. Geometric Design and Concept

The development of the deployable structure followed a bottom-up design approach, where material properties and their iterative refinement informed design choices. This method prioritised the inherent characteristics of the novel biocomposite pultruded profiles, shaping both structural solutions and connection strategies, ensuring compatibility between material behaviour and construction techniques. Emphasising non-invasive connection methods, the design process was tailored to the material’s properties, geometry, and performance capacity. Initial design explorations focused on rope-threading methods as an alternative and simplified, non-invasive approach for creating quick universal joints for testing purposes [29]. This method offered a flexible, efficient solution for connecting components while maintaining ease of assembly and disassembly, ideal for rapid prototyping and experimentation. Early shape experiments were conducted using small-scale models made from hollow pasta tubes, geometrically resembling the pultruded profiles, allowing for the hands-on testing of string-based connections. Furniture was chosen as the application context, offering a practical testbed for structural concepts. Early prototypes included a deck-chair-style structure inspired by scissor mechanisms (Figure 1a) and a geodesic-domes-inspired design using profiles connected in star-shaped modules (Figure 1b) [30,31]. However, these early designs lacked the desired level of deployability and flexibility, prompting a re-evaluation of the scissor mechanism’s mechanics for improvement.

During the design development phase, tests were conducted on movement patterns inspired by scissor structures. The main design principle involves four interconnected elements joined at their ends to form a continuous loop with a diagonal crossing, creating an “IXI” shape. In this configuration, the vertical elements are represented by “I” and the diagonal crossing elements are represented by “X”, forming an ‘X’ between two ‘I’s. This flexible configuration, with connections limited to four points, enabled the system to deploy, as illustrated in Figure 2. This system demonstrates a full range of motion, with deployment angles varying from 0° to 180°, enabling a complete transformation from a flat state to spatial configurations. The novelty of this design emerged from a material limitation—the biocomposite profiles could not support penetrative connections at their centres, as indicated in Section 1.1—a feature typical of conventional scissor mechanisms. This material constraint led to the development of a unique design approach, where pivot points were placed at the ends of the bars rather than the centre. This shift in pivot placement became a key design principle, facilitating movement and enabling height and width variations without a central joint. The result is a deployable system that responds to material limitations while offering a novel, adaptable mechanism for transformation, allowing for versatile architectural and functional applications.

This single-degree-of-freedom system formed the foundation for a deployable structure transforming from a flat (2D) configuration into a fully expandable three-dimensional (3D) form. The final model integrated insights gained from earlier experiments. The scissor mechanism shown in Figure 3, which permitted variations in height and width, was strategically integrated with the modular concept derived from geodesic geometries. To achieve a functional deployable 3D system, the initial IXI-shaped 2D geometry was replicated three times and interconnected at its six corresponding edges or vertices, forming a spatial network. Consequently, the joining mechanism had to evolve from simple pin joints to universal joints. These advanced connections enabled deployment and provided multi-directional freedom of movement, accommodating the system’s expansion and contraction while ensuring structural integrity. Various types and configurations of universal joints were evaluated and refined through the case studies, assessing their kinematic efficiency, load distribution, and adaptability to different deployment scenarios.

Continuing the experimentation, a small-scale model of the final solution was created, where three scissor units were linked using an elastic string (Figure 4). This small-scale prototype successfully validated the final design, consisting of 12 elements arranged in the configuration IXIIXIIXI. The length of these elements could vary depending on the concept and specific design requirements. For the final structure, a modification was introduced to simplify assembly, reduce material use, and minimise weight. One leg from each double-leg pair was removed, resulting in a nine-element configuration, XIXIXI, instead of the original twelve. A key feature of the final design is its ability to deploy, enabling adjustments to both the structure’s height and the size of its top and bottom resulting surfaces. This flexibility allows the structure to serve multiple functions, such as transforming from a table into a stool.

The novelty of the final system lies in its material-driven design approach, where the limitation of biocomposite profiles led to the innovation of pivot points at the ends of the elements, allowing for smooth movement and deployment without central joints. This solution enabled both the structural adaptability and the ease of transformation necessary for real-world applications. Two case studies were developed and constructed to validate the proposed geometric system, which will be detailed in the following chapters. The first case study presents a deployable furniture piece that transforms from a stool to a table of adjustable heights, utilising string threading techniques for its joining system. The second case study investigates architectural applications, focusing on an adaptive facade system incorporating biocomposite universal joints.

3. Case Study 1: Threading Methods in Furniture Scale

Deployable systems offer versatile applications across different scales. Furniture serves as a small-scale structural application, providing a practical means to test the system’s reliability, making it an ideal choice for the initial examination of the design concept. As a deployable system, this furniture piece can transform from a flat state, suitable for storage and transportation, into a functional spatial configuration. To further explore its deployability, it was decided to test the design in different deployment stages, allowing for multiple use cases. In this scenario, the system can function as a table or stool at varying heights, requiring an additional element to serve as a tabletop or seating surface. Based on these application scenarios, specific design requirements were established, particularly in relation to ergonomics. The weight capacity was set with a minimum safety margin of 80 kg to support an adult. For seating configurations, an initial minimum height of approximately 55 cm was considered, though flexibility was maintained to accommodate different table heights. Recognising the variability in use cases, a general height range between 50 cm and 70 cm was established.

In the first case study, inspired by the threading methods used in the small-scale models, a string was used as a connecting element, exploiting the tubular geometry of the biocomposite profiles to enable multi-directional movement. This innovative use of universal joints, formed with strings, departed from traditional hinge- or pin-based systems. The method preserved the integrity of the biocomposite material while improving flexibility and deployability. Two threading techniques were tested, examining various material combinations and their effectiveness in connecting joints. Locking mechanisms were also tested, integrating an additional element serving as the seat. This evaluation was essential for assessing the structure’s stability and resistance to weight. The following sections of this chapter will explore these details in depth.

3.1. Threading Method 1: One-Loop Method

The first experiment, using string to connect all the profiles and form the structure, was conducted using a single continuous loop. The profiles were arranged on the floor in the configuration XIXIXI, as shown in Figure 5, where each segment represents an individual profile (for example, [AD], [BE], etc.), with their endpoints labelled from A to F. The string was threaded through the tubular profiles, following this specific path: threading began at point A on the first diagonal profile. It proceeded forward, passing through each profile’s connection points in the order A-D-E-F-C-B-A. Upon reaching the last vertical profile, [BA], the string was threaded back towards the starting point, covering the remaining profiles along the path A-F-C-D-E-B. Some profiles were threaded a second time during the return path, particularly profiles [DE] and [FC], where the string passed through these leg profiles twice. The string’s starting and ending tips emerged from the two diagonal profiles at points A and B. To complete the loop, the loose end at point A was tied in a knot at the bottom of profile [BA] at A, and the tip at B was connected to the top of profile [BA] at point B. This process resulted in the formation of the flat configuration of the structure, as shown in Figure 5, where the string is represented in red and the profiles in black. Figure 6a presents this geometry realised using the pultruded profiles.

Two prototypes were developed to test material combinations using the one-loop method. Specifically, different string types were explored, focusing on their material properties, particularly elasticity, and their suitability for integration into the system.

3.1.1. Prototype 1: Polyester Cord (Non-Elastic)

Using the one-loop threading method, the first prototype was constructed with three pultruded profiles measuring 70 cm (vertical profiles—I) and six profiles measuring 100 cm (diagonal profiles—X). These were connected using a 4 mm white polyester cord totalling 830 cm, including additional tolerances. The structure’s maximum height was achieved when the I-profiles were perpendicular to the floor, resulting in a maximum height equal to the length of the leg profiles. This height was chosen by calculating the midpoint between standard seat height and table height. The prototype weighed approximately 2.4 kg.

At this stage, the structure was fully deployable and flexible, but to maintain stability in a fixed position, a tension cable was added at the base (Figure 6b). The primary objective was to test whether the structure, with its string connection system, could bear a load exceeding 80 kg without failure. A wooden plate was placed on top of the structure to perform these tests, and various weight tests were conducted, including both human and material loads. The tests showed that the structure could support a total weight of 100 kg.

However, several issues arose. The polyester cord inserted in the profiles could not be sufficiently tightened, which resulted in the joints between the three profiles lacking the necessary tension to hold them closely together (Figure 6c). Additionally, the overall diameter of the structure proved to be too large for its intended use, necessitating adjustments to the profile lengths for future prototypes.

3.1.2. Prototype 2: Elastic Rubber Rope

Following the one-loop threading method, the second prototype was scaled down, with the vertical profiles (I) measuring 56 cm and the diagonal profiles (X) measuring 80 cm. These profiles were connected using an 8 mm black elastic rubber rope coated with braided polyester, replacing the 4 mm white non-elastic polyester cord used in Prototype 1 to address the tension issues identified in the earlier version. This modification resulted in a structure that exhibited greater stiffness and could stand independently without a tension cable. The elastic rope was manually stretched to its maximum capacity; however, the tension cable was still added to perform the weight tests. The tests demonstrated that the structure could support over 80 kg, regardless of the type of string used.

Despite the improved internal tension, deformation at the joint connections between the profiles still occurred, irrespective of the elasticity of the rubber rope. This issue was likely caused by the one-loop threading method, which failed to create a proper junction at each joint connection, similar to the issue observed in Prototype 1. Specifically, the string properly connected only two of the three profiles. It became clear that a more effective threading method would be necessary to ensure that all three profiles were securely attached and aligned in their final positions.

3.2. Threading Method 2: Three-Loops Method

A three-loop system was developed to achieve three connections per joint. The strings used to connect the profiles are visualised in Figure 7 in red, blue, and yellow, and in Figure 8a as the newly developed universal joint. A consistent method was applied to all six joints, ensuring each string loop followed a distinct path, preventing any loop from passing through the same joint more than once. For example, at junction point B, the connections were made as follows: the red string loop connected profiles [AB] and [BE], the blue string loop connected profiles [EB] and [BC], and the yellow string loop connected profiles [CB] and [BA].

This approach was validated through experimentation on a small-scale model using three elastic strings. The resulting structural model demonstrated remarkable stability, with the three profiles at each joint securely locked next to each other, preventing loosening once all loops were closed.

The second prototype was dismantled to minimise material waste, and the profiles were reused to test the three-loop threading method. The prototype was reassembled with three 8 mm black elastic ropes, each 420 cm long, plus 10 cm for margins. The length of each loop was calculated by adding the lengths of four diagonal and two vertical profiles. The resulting joints were flexible once the method was applied, and the profiles remained securely positioned (Figure 8a). The three-loop method proved effective, demonstrating significant internal tension and stability (Figure 8b), as the structure no longer required the tension cable to support itself. Before this, the tension cable had been used as a locking mechanism to maintain the structure’s stability, keeping it at a specific height. It was indispensable for the weight tests but did not perform adequately during testing. This prototype was the basis for developing a furniture piece where the tension cable presented several problems. It was difficult to adjust precisely for multiple height settings, as this posed a potential safety hazard and was also aesthetically disruptive (Figure 8c).

Adding a seat or tabletop marked the final steps in transforming the structure into a fully functional piece of furniture. This raised the question of whether the tension cable could be eliminated and whether the structure’s other elements could serve the same purpose. Practical tests were conducted to investigate whether the seat could replace the tension cable, acting as a locking mechanism and compressive element from the top rather than as a tension element from the bottom. The main objective was to determine under what conditions this replacement would be viable.

3.3. Top as a Functional and Structural Element

The final element to complete the structure is the surface, which will function as the stool seat or tabletop for table applications. This element serves a functional purpose and plays a critical role in the geometry and structure of the system. This chapter outlines the trials and tests conducted to finalise the structure.

3.3.1. Seat Attachment Options

The geometry of the developed structure represents, in abstract form, a tetrahedron with a truncated top. The seat was designed to complement this geometry, taking a triangular shape that aligns with the structure’s top and base while serving as a crucial structural component. In its initial configuration, the seat was fabricated using 15 mm-thick plywood, with slits introduced for securing the seat using a flat belt string. The resulting equilateral triangle had sides measuring 56 cm, with the sharp corners trimmed for safety and ergonomic reasons. Initial tests showed that the seat could resist moderate loads, with the seat absorbing compressive forces effectively. However, excessive movement between the seat and the structure was noted, indicating the need for further refinement. The seat can be used to secure the structure at varying heights during deployment, functioning as a locking mechanism that effectively replaces the tension cable.

To attach the seat, slits were introduced to accommodate a flat belt string, securing the seat to the structure. Initial tests showed that the structure could resist moderate load, with the seat absorbing compressive load. The initial tests showed that the structure could resist moderate load, with the seat absorbing compressive load. However, the seat did not sufficiently secure the structure, causing excessive movement. This behaviour indicated that the tension cable was unnecessary under lighter loads, as the seat effectively distributed compressive forces through the frame. However, the structure required a tension cable for heavier loads to counteract lateral movement and maintain stability. In its initial configuration, the strap passing through the slits allowed excessive movement between the seat and the structure (Figure 9). This highlighted the need for further refinement, including stronger attachment methods, to ensure that the seat could reliably serve as a stable compressive element at the top of the frame.

An alternative approach to securing the wooden seat was explored using 4 mm polyester cords tightly secured around the seat at its three corners. The cords were threaded through drilled holes, sized just large enough for the cords to pass through. Attaching the top joints closer to the seat’s edges made the leg angle steeper, resulting in a greater height for the stool. The connection between the seat and the structure was reinforced with the non-elastic 4 mm cord, replacing the previous string connectors. The 8 mm black elastic rope inside the structure was also substituted. Two weight tests with loads of approximately 65 kg and 80 kg confirmed that the modified seat configuration effectively eliminated the need for a tension cable.

Replacing the tension cable necessitated the seat to fulfil dual roles: locking the deployable structure at defined heights and stabilising it under varying loads. The seat was required to provide compressive stability to resist lateral movement while maintaining the design’s simplicity. Height adjustment was achieved by altering the inclination of its legs, which depended on the offsets of the seat attachment points. To enable different height configurations, five sets of attachment points, spaced 1.5 cm apart, were drilled into the seat (Figure 10). By positioning the attachments at varying distances, the legs could change their angles, directly influencing the structure’s overall height. In the initial configuration, the excessive movement of the seat was noted, which highlighted the importance of securing the attachment points properly to maintain stability and improve load-bearing capacity. To fulfil the second requirement, the stool underwent gradual weight testing to assess its load-bearing capacity and identify any potential breaking points across the five positions. The positioning of the attachment points significantly affected the structure’s stability and load-bearing capacity. It is essential to note that the reference to the seat edges applies only to this specific seat size. For designs involving different dimensions, such as tabletops, the reference points must shift to account for the distance from the centre of the surface.

3.3.2. Load Capacity Tests and Attachment Points

A series of systematic tests were performed to evaluate the structure’s load capacity in combination with the seat and its varying attachment points. The timber base, equipped with five pre-drilled attachment points (Figure 10), was subjected to incremental weight loads at the different attachment positions. For each test, weights were progressively added while the timber base was secured at a specific attachment point, allowing observations of structural response (Figure 11).

Table 1. Load tests overview.

	Test 1		Test 2		Test 3		Test 4
	T1	T2	T1	T2	T1	T2	T1	T2
Attachment point (cm)	8		2		3.5		5
Height (cm)	44	35	55.6	55.6	53.5	52.7	52	49
Weight (kg)	5	20 (25)	0	150	0	150	0	80 (90)
Height (cm)	44	35	55.6	55.6	53.5	52.7	52	49
Bottom width (cm)	111	130	69.5	72	75	79	84	91
Top width (cm)	35	32	49.8	50.6	47.3	46.5	44	40
Angle (°)	49	35	80	79	76	74	69	64

summarises the outcomes, detailing the structure’s dimensions—height, width, and leg angles—before (T1) and after (T2) adding weights. The data comprehensively compare the sustained loads and the resulting structural adjustments. The overview highlights the influence of different attachment points on the structure’s movement and stability, offering insights into its performance under varying conditions.

In Test 1, the structure’s height was 44 cm, with the legs deployed at a 49° angle. To achieve this position, the seat attachment was secured with an 8 cm offset from the edges, placing the attachment points closest to the centre of the triangular seat. The structure failed under a load of 25 kg, showing deformation with each incremental weight increase. This result confirmed that the load-bearing capacity was insufficient in this configuration. In Tests 2 and 3, the structure’s top was attached 2 cm and 3.5 cm from the seat’s edges, providing the widest spacing between them (top widths are noted in the table). These configurations successfully supported weights up to 150 kg without any signs of failure, indicating that steeper inclinations enhanced the stability of the structure, with the seat providing sufficient compressive support. In Test 4, the seat attachment was secured with a 5 cm offset from the edge, positioned slightly closer to the centre than in Tests 2 and 3. This configuration successfully supported a target weight of 80 kg but failed at 90 kg. Initially, the structure displayed significant stability. However, at 90 kg, the structure broke instantly without prior deformation, resulting in some profiles splitting along the fibres due to the high tension.

Across all tests, the height either decreased or remained nearly constant when comparing the measurements of T1 and T2. For example, reductions were observed in Tests 1 and 4, while minimal or no changes occurred in Tests 2 and 3. The bottom width consistently increased from T1 to T2 in all tests, with variations in the magnitude of this change, the most significant being in Test 1. Similarly, the angle consistently decreased from T1 to T2 across all tests, with reductions varying in degree but following a consistent trend. The wider attachment spacing used in Tests 2 and 3, where the attachment points for the top joints were positioned closer to the edges, provided optimal stability and compressive support, allowing the structure to support weights up to 150 kg without failure successfully. These results indicated that the positions of Tests 2 and 3 were the most stable. This finding confirmed that, for this design, the wooden seat could replace the previously used tension cable, provided that the attachments were positioned at least 3.5 cm from the edges (Test 3). The farther the load is distributed toward the extremities, the greater the structural capacity.

For different use cases, particularly for a lower coffee table where the structure needs to be positioned at a lower height, the attachment points on the tabletop would need to be placed further from the centre than in Test 3. In this case, the string passing through the holes at a lower position in the structure would act as a tension cable from above, integrated within the tabletop. In this scenario, a larger top should be used for geometrical and functional reasons.

As an overview, the tests showed that the load-bearing capacity of the developed structure is significantly influenced by the placement of the attachment points. The wider spacing of the attachment points, particularly when positioned at least 3.5 cm from the edges, provided optimal stability and support, allowing the structure to withstand up to 150 kg without failure. Central attachment points resulted in insufficient stability, with the structure failing at lower weights. The findings also highlighted that for different use cases, such as a coffee table, adjusting the attachment points further from the centre and using a larger top would enhance load distribution and structural performance.

3.4. Results of Case Study 1

The development of this structure, particularly in the context of the furniture application, is illustrated in the following development diagram (Figure 12). Beginning with the foundational 2D geometry and the core principle of IXI, a deployable structure was designed to function as either a stool or a table with adjustable height. The diagram outlines the evolution of the structure, highlighting critical design decisions such as the selection of connection materials, specifically the strings threaded through the tubular profiles. The method of looping these strings within the geometry of the profiles demonstrates the interplay between the material properties and the structural design. Furthermore, the integration of the top elements, which serve both functional and structural purposes, illustrates how they contribute to the overall stability and adaptability of the structure.

3.4.1. Design Overview

In the final design, the pultruded profiles were cut to lengths of 56 cm (for the three leg profiles) and 80 cm (for the six diagonal profiles). The structure used two string materials: an 8 mm black elastic rubber rope and a 4 mm white non-elastic polyester cord, utilising their tensile and compressive properties. The three-loop threading method was applied, with a total material length of 4.5 m for each type of string, used three times. A black rubber cap was added to the profiles at each foot joint, serving as a material protector and a foot detail for the table or chair. The material overview is presented in Figure 13.

The structure allowed for adjustments in the top surface’s height and diameter. To accommodate this, two top elements were designed to enable the structure to function as a stool or a table. These tops served as locking mechanisms and compressive elements, allowing the structure to support weights up to 150 kg. A triangular plywood seat, 15 mm thick and with a side length of 56 cm, was connected beneath the structure using a 2 m-long 4 mm polyester cord. Holes drilled in the seat with offsets of 1 cm and 3.5 cm from the corner edges allowed for height adjustments of 56 cm and 53.5 cm. The second top, a circular tabletop with a diameter of 120 cm, was made from the same plywood material and connected using the same type of polyester cord, with an overall length of 3.5 m. The holes drilled in the tabletop, with offsets of 4 cm and 24 cm from the centre, enabled height adjustments of 45 cm and 58 cm.

3.4.2. Structure Assembly

Three loops of the elastic and non-elastic strings were used to connect the profiles, following the Threading Method 2, as outlined in Section 3.2 (Figure 14a). Only knots, specifically reef knots, were employed to secure the strings inside the structure, with each loop beginning and ending at a different foot joint. The mechanical advantage of this knotting technique lies in its ability to maintain stability under both tension and compression while also being easy to disassemble, even after being subjected to significant weight.

The top is attached to the structure using a single-threaded string, which is looped through the first hole in the timber seat, passed under the structure’s top joints, and then threaded back through the second hole in the timber seat (Figure 14b). This process is repeated for all three joints. Once the string is pulled tight, it is secured below the top with a cord stop positioned under the final set of holes. The threading system of the top is designed to be secure, with the cord stop providing sufficient strength at the closing point without additional reinforcement. Adjusting the height of the table between attachment positions takes approximately 8 min, while changing the stool height requires around 3 min.

The main structure, consisting only of the profiles and strings without the seat, weighs 2.5 kg. When the wooden seat is added, the complete stool weighs 4 kg. The structure can be flat (when the top elements are not attached) or adapted into four selected shapes, offering two different functions. The final design of the deployable structure presents numerous advantages. Combining strings and pultruded profiles ensures high self-tension and minimal displacement under load. Additionally, the interchangeable tops provide flexibility, allowing for height and diameter adjustments, enabling the structure to transform from a stool into a table (Figure 15).

3.4.3. Insights from Case Study 1

The first case study at the furniture scale demonstrated how deployable systems can be adapted for practical applications, validating their feasibility beyond conceptual design. The novelty of the Delta IXI system lies in its material-driven approach, where the inability to use penetrative connections in the biocomposite material led to the integration of an alternative pivot placement into the overall design. This placement, combined with a non-invasive rope-threaded system, applied in the furniture-scale application, enabled the development of a deployable mechanism that transitions from a flat state to a functional form without relying on traditional scissor joints. Unlike conventional deployable structures, this system integrates a continuous tension-based assembly, where flexibility in deployment stages allows for multiple use cases. The ability to lock the system at different heights expands its adaptability, accommodating ergonomic requirements while maintaining structural integrity. The system can also be easily collapsed into a flat state, facilitating convenient transport and storage, thereby enhancing its practicality. In this first case study, the key innovation is primarily linked to the threaded connection methods, demonstrating how such systems can be applied in real-world scenarios. By replacing conventional mechanical fasteners with a rope-threaded assembly, the design showcases an alternative approach to structural connections, leveraging material constraints to enhance functionality. This highlights the potential for scalable modular solutions in both furniture and broader architectural applications. As such, the principles demonstrated here can be further explored in larger-scale, multifunctional structures, providing a foundation for versatile and sustainable design solutions.

4. Case Study 2: Adaptive Facade System

The successful realisation of the Delta IXI concept in a small-scale structural prototype confirmed its adaptability, stability, and capacity to support significant loads relative to its lightweight design. Its adjustable configurations highlighted the system’s versatility and potential for reconfigurable applications. These findings have been encouraging for the potential expansion and integration of the concept into larger architectural applications. While manual adjustments in the first case study were effective in a furniture application, scaling up the system might introduce practical limitations, prompting the development of a kinetic system. Given the system’s inherent deployability, it is particularly suited for kinetic designs and dynamic applications. Therefore, further research explored the adaptation and scaling of the system for implementation as part of an architectural facade, considering the structural and material insights gained from the previous case study.

4.1. Design and Modularity

The design focused on modularity, multiplying units to cover a designated facade area and creating an adaptive system that dynamically responds to weather conditions, particularly the sun’s position. To ensure effective shading, the system included a supporting grid structure and a kinetic mechanism for precise actuation and deployment. An electronically controlled system was developed to enhance functionality and automation. An additional element was incorporated to improve shading performance, adding both functionality and aesthetic value to the system.

The deployable model, Delta IXI, functioned as a modular and scalable system, capable of expanding both horizontally and vertically within a customised grid. The grid, designed as a structural framework, adopted a triangular arrangement of equilateral triangles, aligning with the model’s geometric principles. The vertices of each triangle acted as key intersection points for the modules in their flat configuration, with the three amplitudes guiding movement during deployment. As the modules were attached solely to these amplitudes, the original grid became redundant. The amplitudes then functioned as sliding rails for the facade components. The final supporting grid, formed from these amplitudes, created a tessellated cubic structure, streamlining the framework and enabling module integration in two directions. The grid’s transformation is illustrated in Figure 16. Beginning with the triangular grid (a), the blue lines indicate the triangle’s amplitudes (b), which become the primary grid elements (c). On this new grid, multiple Delta IXI modules can be attached. To achieve full coverage, the modules are arranged in two distinct orientations, rotated 180°, as shown in blue and purple (d). This configuration ensures seamless facade coverage when the modules are deployed. The design allows for flexibility, as both module size and grid layout can be adjusted to meet different facade requirements.

The material used for the profiles was previously tested for its mechanical properties in earlier work (as indicated in Section 1.1), demonstrating its suitability for structural applications. Additionally, the design of the Delta IXI module was assessed for its load-bearing capacity. In the facade application, no direct load scenario is present, so at this stage, the material and system are considered adequate for implementation. A key design limitation lies in the maximum possible length of a single pultruded profile, restricted to 2 m, as confirmed by bending tests. The main Delta IXI module can be adjusted and multiplied to accommodate different facade sizes. While in the furniture-scale scenario, the module size was determined by ergonomics and functionality; the facade application offered greater flexibility, with dimensions varying based on design requirements, overall coverage, and structural considerations.

To enable adaptability, parametric modelling was integrated, allowing precise control over module sizing and grid configurations. A parametric model was developed using McNeel’s Rhinoceros 7.0 and Grasshopper 3D to enhance design flexibility and customisation. This model followed a two-phase approach to ensure adaptability.

In the first phase, the core principle of the Delta IXI system, as described in the previous section, was parametrically generated using simple mathematical formulas to achieve deployability while aligning with the original design objectives. The process began with the insertion of a single point, around which an equilateral triangle was generated along with its three amplitudes. To form a spatial geometry, a second triangle was placed vertically at a defined distance from the first. Following geometric principles, nine lines were then generated, representing the structure’s primary elements. As illustrated in Figure 17, these lines interconnect the points of the two triangles, with each point of one triangle connecting to all three points of the other. For example, A1 connects with B1, B2, and B3. Geometrically, one triangle is always smaller than the other. The parametric model relies on two main parameters: x and y. Here, x represents the amplitude length of the first triangle, while the second triangle’s amplitude length is given by y − x. The distance between the two geometries is determined by the formula: if x < (y/2), then x, otherwise (y − x). In this model, parameter y must be defined, while parameter x allows the visualisation of the deployable system’s movement.

In the second phase, the functional parametric model of the main module served as the foundation for testing various modular configurations. It was further refined for facade applications, enabling module multiplication to adapt to customised facade dimensions and enhance shading efficiency. Additional components for the supporting grid and shading elements were integrated, resulting in a fully functional system. The parametric model incorporated three primary parameters: the triangle width (w) of the primary grid and the overall grid size, defined by the number of elements horizontally (Ex) and vertically (Ey). The grid width could be manually specified by the user or automatically adjusted based on the total facade area to ensure a tailored fit. To visually demonstrate the deployment of the facade modules, the same numerical slider used for the module’s movement (parameter x) was incorporated. This enhanced flexibility, enabling dynamic adjustment along the grid rails. The modules could either converge towards the triangle centres for effective shading or diverge towards the vertices to maximise light transmission. To aid in visualisation, a triangular shape was integrated at the top triangle, providing a clear indication of the facade’s open and closed states. This adaptability ensured a balance between shading and light permeability, addressing diverse environmental and design requirements. The initial configuration assumes that all facade modules deploy simultaneously, maintaining uniform light transmission. However, this behaviour can be adjusted, allowing modules to open or close in varied patterns to meet alternative user preferences and specific functional scenarios.

Figure 18 presents an example of a six-by-three module grid, illustrating the deployable movement of the facade and the transition between open and closed configurations. The diagram highlights how the modules shift positions, altering the facade’s permeability to light and air. The grey shape represents the shading elements, which can be stretched or retracted to modify the level of coverage. When fully extended, these elements create a continuous surface, providing complete shading, whereas in the open configuration, they retract, allowing maximum light penetration. This dynamic adaptability enables precise control over shading, accommodating varying environmental conditions and user preferences.

4.2. Concept of Shading Optimisation

The proposed shading system introduces an adaptable solution for optimising solar exposure in building facades. Designed to respond dynamically to environmental conditions, it can efficiently regulate the amount of light entering a space, contributing to energy savings and occupant comfort. By adjusting in real-time, the system can minimise glare, improve thermal regulation, and enhance overall energy efficiency. For example, in a two-storey building, this system can adjust the facade’s shading to optimise solar gain throughout the day. The illustrated example features a grid of 1 by 1.75 m (Figure 19), with a total building height of 7 m. The system functions as an adaptive sunshade, dynamically adjusting to control solar gain and regulate light levels, allowing for varying degrees of shading, providing up to 60–70% daylight when fully open and as low as 10–20% when closed. This adaptive feature enables the optimisation of the window-to-wall ratio (WWR) across various building orientations, as well as for different times of the day within the same orientation. As a result, it minimises direct sunlight during peak hours, reducing glare and enhancing thermal comfort by regulating interior temperatures. This, in turn, contributes to improved energy efficiency by decreasing the reliance on artificial cooling.

To further enhance adaptability, the system could integrate sensors that monitor environmental conditions, allowing for automated real-time adjustments. This capability would enhance comfort and sustainability, ensuring effective sun shading throughout the day. The flexibility of the system allows it to respond dynamically to changing conditions throughout the day, promoting a more sustainable and comfortable indoor environment. This adaptive facade could also improve the building’s aesthetic appeal, offering a contemporary, cutting-edge design element that adapts to both functional and environmental needs.

This section has outlined the overall concept of the facade, focusing on its adaptability, performance, and design potential. The following sections will delve into the technical aspects of the system, including its connection mechanisms, material selection, and fabrication processes. These elements are fundamental to translating the concept into a functional architectural solution, ensuring its durability, efficiency, and seamless integration. By examining these aspects in detail, the discussion will provide a comprehensive understanding of how the shading system operates in practice, supporting both environmental performance and design flexibility.

4.3. Concept of Materiality and Connections

One of the primary goals of this case study was to increase the structure’s bio-content. Biocomposite materials were prioritised for both the grid and connection components, aligning with sustainability goals. The supporting grid was constructed using the same biocomposite pultruded profiles, ensuring a cohesive design that expanded their application. Material exploration also focused on the nodes, where bio-based connectors were tested for their feasibility and strength in real-world applications. Finally, the shading elements required a highly stretchable textile material to accommodate the geometric transformations that occurred during deployment. This ensured that the system not only functioned effectively but also performed consistently under changing environmental conditions, meeting both aesthetic and functional objectives in the final design.

The concept of the adaptive facade required a novel approach to element connections, addressing the specific demands of a facade-scale structure. While rope threading proved effective for furniture-scale applications, the facade system necessitated more robust and durable joints. To address this, a series of connection strategies were developed, focusing on three key aspects: (1) connecting elements within the main Delta IXI module, (2) securing the module to the supporting grid, and (3) integrating and attaching the shading element.

To replace the previously used threading methods, universal joints were developed to seamlessly connect the original deployable modules, while also incorporating attachments for the railing and shading elements. Additionally, custom joints were designed and fabricated to support the grid structure, ensuring both stability and flexibility within the system. A stretchable textile material was integrated and attached to the existing joints within the framework to form the shading. As the system deployed, the textile stretched and conformed to the changing geometry, effectively achieving the desired shading effect while maintaining structural integrity.

The movement of the system is a crucial aspect of its functionality, defining how each module operates within the broader facade structure. This movement is directly linked to the design and fabrication of the connections, which were specifically developed to facilitate the system’s dynamic operation. The system includes four main types of connectors, as illustrated in Figure 20. The system’s movement was initially defined at a module level. For the facade system, with the integration of the grid, movement commenced at the three vertices where the grid intersected the main facade (A1–3). To facilitate this movement, the three vertices must slide along their respective rails (R1–3) at an equal speed and in the same direction, converging at the central point (C1). To achieve this synchronised motion, an electronic kinetic system was developed, with the central point (C1) serving as the control hub for initiating movement, driving the mechanism along the rails (R1–3), and extending to the endpoints (A1–3). The connectors (points A) travelled along the rails through actuation, either converging towards the centre or diverging back towards the ends (points G).

4.4. Kinetic System for the Adaptive Facade

The developed kinetic system was powered by a motor-driven mechanism controlling movement along the rails. A central connector at the system’s core lies at the module’s centre (C), where the three rails (geometrically the three amplitudes of the base triangle) converge. This connector initially joined the three profiles meeting at the centre, which were part of the support grid and, at the same time, the rails of the system. It also housed a single servo motor, coordinating the overall motion. The motor was mounted on one side of this connector, transmitting rotation at a 90-degree angle to the rails via a bevel gear system mounted on the back side of the connector. The gear mechanism consisted of a central gear equipped with three surrounding pinion gears, each connected to a T8 threaded steel spindle extending along the three rail profiles. As the spindles rotated, three sliders moved parallel along the pultruded profiles, functioning like standard linear actuators, either towards the centre or reverse. These rods were supported by cylindrical bearing holders with bearings to ensure smooth rotation and alignment. The holders and the entire mechanism were secured by bolts and mounted on a customised base for precise alignment. During the prototyping phase, fabrication options were explored to maximise bio-content, involving 3D printing the base using bio-based filament. Additional tests with CNC-milled plywood were also tested (Figure 21).

The threaded rods were joined to three connectors, which slid along the rails to enable the synchronised motion of the facade elements. These connectors were located at points A1–3 of the system (Figure 22A). This second connector was 3D printed to enable the attachment of three profiles on one side while enabling attachment and railing along the grid profile. It incorporated a linear flange ball bearing, a mechanical component that ensured smooth motion and system alignment. It featured a cylindrical flange housing precision ball bearings inside, minimising friction and enabling movement along a linear shaft. To enable attachment to the pultruded profile, the utilised flange had an inner diameter of 25 mm, the same as the profile’s outer diameter. This customised connector enabled sliding along the rail, guided by the spindles. On the opposite side, it integrated a universal connection joint, to which the three profiles were attached. Three of these joints, located at one side of the module, facilitated the deployment of the entire system. Both joints were designed as clamps, made in two pieces to allow the profiles to be inserted and then clamped together and securely fastened with screws. A more straightforward connector type for point B consisted of an expansion anchor with an M10 eyelet, which fit perfectly inside the hollow profiles (Figure 22B). The anchor was securely positioned within the profiles, while the eyelets facilitated the interconnection of the three profiles at this point, allowing for simple wrapping methods to join them.

The joints connecting the grid elements (G1–3) supported the overall structure. These connectors (G) had to be rigid and robust to ensure the system’s stability and maintain support during movement. Two connector types were designed based on their grid position: one for the central locations where six elements met and another for the edges where only three converged. A 3D model of these connectors was developed and optimised for 3D printing using bio-based filament. Finally, to protect the edges of the biocomposite profiles from friction and weathering while enhancing the aesthetic quality of the element, polyethylene (PE) cups were applied to the ends of all pultruded profiles (Figure 22B). The hollow sections of the profiles were used to route the electrical cables along the grid, enabling the system’s operation while maintaining a clean aesthetic. These cables ran throughout the facade, ensuring a seamless connection to the power source. This integrated setup facilitated efficient movement control and supported the dynamic functionality of the facade system.

The final element of the system was the shading component, for which several options were explored. The concepts focused on integrating a stretchable textile that could provide varying levels of shading depending on the system’s deployability. These options involved attaching the textile at multiple points to offer full shading while manipulating light and shadow. The most straightforward configuration attached the textile at three outer points of the modules (B1–3), forming a triangular shape. This setup complemented the overall design, offering maximum or minimum shading. Another option involved attaching the textile at all six system points, creating more dynamic shading effects. These connections formed partial triangulations that helped maintain the textile’s tension, even in extreme positions. The textile had to be cut to the required dimensions to make the shading element, with eyelets inserted at the connection points. These eyelets allowed for easy attachment using loops around the end connections.

4.5. Built Prototype

To demonstrate the implementation of the system, a single module was constructed and assembled, showcasing the developed kinetic mechanism. This module, along with part of the supporting structure, was built to a 1:1 scale, allowing for a tangible representation of the design. The grid was interconnected using precisely CNC-machined connectors, which were then mounted onto an existing timber support structure. To ensure compatibility with the given support structure, which had a spacing of 68 cm, the resulting module was designed with profile dimensions of 78 cm. The sliding connectors were 3D printed using flax fibre-reinforced PLA, adding a sustainable material choice to the design. A cotton textile was attached to all six system points to demonstrate the shading capability of the system. One module (Figure 23) was constructed and displayed at the International Building Exhibition (Internationale BauAusstellung, IBA27) during the summer of 2023 at the ILEK Tower on the University of Stuttgart Vaihingen campus. The exhibition, “Adapt and Thrive: Biocomposites for Dynamic Architecture”, highlighted innovative approaches to architectural design, specifically focusing on the potential of biocomposites in dynamic applications. Within this exhibition, the kinetic system was integrated into the facade element, offering visitors the opportunity to observe its dynamic interactions and real-time functionalities. The display not only emphasised the aesthetic qualities of the design but also demonstrated its smooth deployability, validating both the effectiveness and the potential of the deployable system in real-world settings.

The prototype showcased here serves as a proof of concept for the deployable system, with the potential for scalability and adaptation in future implementations. This prototype was placed within an interior space, serving as a demonstration of the system’s geometry and movement, rather than being applied to an actual facade. It was designed to showcase the system’s kinetic properties and how the modules can interact dynamically. While it does not yet provide real facade functionality, the system was showcased to illustrate the possibilities of such a design. The system’s modular design allows for easy multiplication, making it adaptable for larger surfaces and complex geometries in future applications. The integration of multiple modules is seamless, thanks to the modular nature of the connectors and the system’s adaptability. Future work can expand upon this foundation, adjusting the system for more diverse architectural scales and functional requirements. The system’s flexibility not only accommodates a wide range of facades but also provides opportunities for further development in dynamic architecture, offering shading and environmental control across more complex structures.

5. Conclusions

The main outputs of this research are centred around four key topics: (1) the application of biocomposite pultruded profiles in deployable architecture, (2) the integration of dynamic movement through material and connection design, (3) the development of sustainable and scalable architectural solution, and (4) recommendations for future research to enhance building performance and sustainability. These areas collectively highlight the potential of the Delta IXI system in shaping the future of adaptable, environmentally responsive architectural designs.

5.1. Biocomposite Pultruded Profiles in Deployable Architecture

The Delta IXI system demonstrated the potential of novel biocomposite pultruded profiles in deployable architectural applications. By integrating sustainable materials and innovative design approaches, the research showcased the versatility and adaptability of these profiles across different scales, from furniture to architectural facades.

5.2. Dynamic Movement Through Material and Connection Design

The development of the deployable structure merged design principles from mechanisms on deployable geometries, with a strong focus on the material properties of biocomposites and non-invasive connection methods. Initial experiments using small-scale models facilitated iterative testing and refinement, ultimately resulting in a flexible, multifunctional structure capable of transitioning from a 2D to a 3D form. The integration of offset pivots and universal joints proved essential for accommodating the material’s limitation, enabling the system’s movement and flexibility. The final design, with its adjustable height and surface dimensions, demonstrated its versatility across multiple applications of various scales and architectural contexts. This process underscores the potential of biocomposite materials in creating adaptable, dynamic structures that meet diverse functional and aesthetic requirements.

5.3. Sustainable and Scalable Architectural Solutions

The furniture application exemplified a range of key features and material adjustments, allowing the structure to serve as both a stool and a table with adjustable heights. Pultruded profiles were precisely cut to form the main structural elements, with different string types employed to create a threading connection system. The adjustable heights of the stool and tabletop further reinforced its practicality. The main structure weighed 2.5 kg, and the complete stool with the seat weighed 4 kg, which indicates the lightweight nature of the structure. The structure supported weights up to 150 kg, demonstrating substantial load-bearing capacity for a lightweight design. However, the system’s complexity and the need for manual intervention in reconfiguring the structure may limit its use for frequent adjustments, though it remains suitable for scenarios where such flexibility is required. The lightweight nature of the structure, along with its adaptability to four distinct shapes, highlights its potential and consideration of the balance between flexibility, load capacity, and ease of use is necessary for real-world applications.

In the architectural context, the adaptive facade system demonstrated significant progress in integrating dynamic elements within the built environment. The realised prototype showcased exceptional adaptability, structural stability, and load-bearing capacity while maintaining a lightweight and scalable design. Parametric modelling facilitated tailored facade configurations, allowing precise control over shading and light transmission, and ensuring an effective response to changing environmental conditions. The system’s modular design, combined with biocomposite materials and kinetic mechanisms, offers a sustainable and flexible solution for future architectural projects. The design of the adaptive facade could be parametrically scaled and expanded to cover an entire facade while optimising shading. Further validation through the 1:1 scale prototype highlighted the seamless movement and adaptability of the facade components, reinforcing the system’s viability. The exploration of bio-based materials also supports the sustainability potential of the design. This case study provides compelling evidence of the Delta IXI system’s effectiveness in large-scale implementations, and ongoing research will continue to refine the system, exploring new ways to enhance building performance and sustainability through dynamic facades that respond to both environmental factors and user preferences.

5.4. Future Directions and Sustainability

Future developments offer opportunities to optimise the deployable structure further. In the context of furniture applications, additional research is needed to refine the attachment mechanisms for the top surfaces. While the current design successfully functions as versatile furniture, simplifying and improving the adjustment process between different configurations will enhance the user experience, making it more practical for daily use. The system currently deploys in a planar configuration, as outlined in the geometric concept. However, exploring alternative connection systems could allow for easier deployment in various configurations, enhancing portability and facilitating more efficient transportation. As this is an initial concept, further development of similar deployable systems could open the door for a range of additional applications across different use cases. In the facade application, future advancements could include integrating sensors to make the system more responsive to changing shading needs, enabling dynamic adaptation to environmental conditions. Currently, the motor-powered prototype controls a single module; expanding this functionality to allow individual motors to control multiple modules simultaneously would improve scalability. Moreover, alternative programming strategies could enable the panels to open and close in various patterns, offering increased customisation for shading and functionality.

These developments would further refine the system, bolstering its potential for innovative and sustainable architectural solutions. Future work should focus on optimising material properties, enhancing connection mechanisms, and expanding the range of potential applications for the Delta IXI system in dynamic architectural environments.