In the design studio, 14 different design generators were identified, linked to the broad field of structure (Table 2). Each generator was developed within a cognitive framework, through a cyclic process as described above.
For most of these generators, the applied framework belonged to the field of structural engineering: concepts, principles and logics of structural behaviour and design were applied to adapt and refine the generator. Students operated in this framework by mainly applying structure calculations software, rules of thumb and first principles.
However, some students developed their generators within a cognitive framework belonging to the field of aesthetics, in which for example the personal appreciation of structural form stands central (i.e. away from the cognitive framework of engineering sciences). This led to a division into two main groups of the identified design generators: structural engineering and aesthetics.
For both groups, the final outcome of a generator development, allowed to produce a wide range of qualitative design proposals or conjectures, mostly based on a developed generic catalogue of design possibilities, or by applying explicit and/or implicit design rules or principles.
Another interesting observation is that some students developed their generator through the use of an existing building or type of building. In these cases, this building importantly determined the properties of the generator (e.g. a catalogue of structural interventions in a 19th-century warehouse).
This building dependent development further divides the first group (structural engineering) into three subgroups: generators developed with an existing building (building dependent), without using a building (building independent) and developed with or without using an existing building (mixed).
In the second group (aesthetics) only one type of design generators was identified, developed with and without an existing building determining the final outcome.
To indicate the importance of each design generator, the number of projects in which the generator was applied is indicated in brackets after its title. (Remark: one project can have multiple design generators).
Structural engineering; building dependent
These design generators are developed by using an existing building or a type of building that importantly influences the generator’s characteristics.
Remediate intervention (9 projects)
After analysing structurally and architecturally an existing building or type of building for refurbishment, various spatial interventions are imagined by the student based on qualitative spatial needs (e.g. daylight transmission, floor height, free plan) or other types of architectural investigations (e.g. stripping a church building to its stylistic characteristics). These interventions affect the structure of the building and require structural remediations to maintain its stability. The relationship between intervention and remediation is explored by applying a set of specific interventions and developing different possible structural remediations for them (Fig. 1). These remediations can be developed through structure calculation software, or by applying rules of thumb and simple first principles of structural design. This process generally leads to an informed catalogue of possible types of interventions as inspiration for their own project, or can result in certain design rules or strategies ranging from intuitively understood to specifically defined.
Context-specific addition (8 projects)
This generator is used to explore possible additions to an existing building by thoroughly analysing the building’s structure and selecting (by the student) one or more important structural characteristics for refurbishment. This structural mapping can include soil characteristics, structural order, structure typologies, stress patterns, (non-)supporting walls, foundations, structural history,… By making a personal choice of a few structural characteristics to focus on for the refurbishment design, the design solution space is narrowed down but also made more manageable and is thoroughly explored: examples include focussing on existing supporting walls for positioning a building addition (Fig. 2), using the present foundation setup to add, delete and shift loads, and exploring possible stripping of a building to various structural core systems. This exploration leads to similar outcomes as under Remediate Intervention, of design catalogue, rules and strategies.
Structure Mimicry (5 projects)
The development of this generator starts similarly to the Context-Specific Addition generator, by analysing the structure of an existing building, but differently it involves creating a structural prototype of (part of) this building. This prototype describes a structure as a system of elements with their structural functions and connections, that allows transferring loads to the supports. This prototype is without materialised form or scale and helps to create and explore various materialisations of a new building design based on a mimicry of this existing abstracted structure.
Structural engineering; building independent
These design generators are created without using an existing building or type of building.
Structural Material (1 project)
By exploring the possibilities in form through determining the structural properties of a material (e.g. rammed earth, Fig. 3), design rules are developed for architectural form design. This exploration ranges from structural details and construction elements to the general form.
Structural Product (3 projects)
This generator is similar to the previous one, except that the starting point is a structural product (e.g. Cross Laminated Timber) instead of material: the student explores the different possibilities in structural form with this product to inspire the architectural design process. Besides the structural properties of the product, the structural possibilities in connecting the product determine importantly the possibilities in structural form, and thus architectural form. In this exploration, the student often applies rules of thumb, first principles and structural typologies (e.g. folded structures with Cross Laminated Timber).
Structural Joint (3 projects)
By investigating the constructive conditions (e.g. adding sequence of joining elements) and the force transfers in a structural joint (e.g. in Japanese wood joinery), the constructive and structural possibilities of the joint are mapped to explore possible structural and constructive forms (e.g. skeleton or portal frames) (Fig. 4). Often in this exploration, existing joints or connections (e.g. wooden puzzles) are modified and further developed to fulfil specific design needs (e.g. connecting with different angles or detailing of building envelopes). This exploration is then used as inspiration for architectural design by creating a catalogue of possibilities or by identifying specific design rules to create (skeleton) forms.
Structural Typology (7 projects)
A specific structural typology (e.g. shell or greenhouse structure) is chosen for (an important part of) the architectural design form. This typology is structurally analysed by the student to be able to refine and adjust elements, materials, dimensions and details of this typology (Fig. 5). Through this understanding, architectural form is created following these structural design rules. (This type of generator includes kinetic structures as a typology: here the possibilities of structural form transformations are an important part of the student’s investigation and exploration in adaptive architectural design).
Adaptable (Con)Structures (7 projects)
This design generator does not necessarily find its core existence in only structural considerations but can be closely connected to certain desired qualities in the construction of a design. Such design is generated by focusing on the ability to easily adapt its materialisation (e.g. to change the qualities of the architectural skin). This desire for adaptability leads to an exploration of the interconnectivity of different construction elements and the development of the elements themselves for interchangeability (Fig. 6). These investigations in turn provide an understanding of possibilities and limitations in architectural form (e.g. modular architecture). Based on this understanding, the architectural project is created.
Structural engineering; mixed (building dependent and independent)
These design generators can be developed by using an existing building, but this is not necessary. However, when they are developed with an existing building, it will importantly influence the characteristics of the generator.
Principle Repetition (3 projects)
This generator consists of a structural prototype (cf. Structure Mimicry) with specific internal structural principles (e.g. tensegrity principles), and is used in materialising architectural form through repetitiously applying this prototype and its principles. The prototype is as such a building block of design and free of scale and materialised form. A reciprocal structural system or a portal frame are examples of such prototypes, but they can also be created by the designer with unique features (Fig. 7). The generation of the prototype can be based on an analysis of an existing building structure or independent from a building.
Grid (2 projects)
An exploration of the design solution space occurs through the application of a structural and functional grid, and their displacements and transformations. Here the structural grid is used to snap the structural elements on (e.g. columns and beams), and the functional grid to snap spatial separators on (e.g. walls). By (randomly or controlled) changing both grids, the design process is guided towards unexpectedly new creations of spatial qualities. Two or three-dimensional displacements put the structural and functional grid in spatial conversation while transformations can change orthogonal grids into a more chaotic or organic constellation with an important impact on architectural space creation. These changes can be induced through software (e.g. generative algorithms) or directly by the designer for systematic or random exploration. (The structural (or functional) grid can be determined by an existing building grid in a refurbishment project and thus importantly influence this generator).
Structural Module (9 projects)
In this design process, the architectural form consists of a configuration of similar structural (and materialised) modules. This structural and constructive module is developed to achieve certain self-chosen requirements of for example stability, adaptability, (easy) constructability, material efficiency, joint uniformity, grid planning and reuse. During generator development, the design quality of the module is tested in one or multiple case-specific scenarios for adjustments (Fig. 6). Such scenarios can include a specific existing building that importantly determines the development of the module design outcome (e.g. the applied module dimensions).
Abstract Prototyping (2 projects)
Abstract structural thinking is used to develop a structural prototype capable of transferring the imposed loads to its supports (cf.  ). Such an abstract structural prototype represents a wide range of architectural design solutions. Exploration of the design solution space occurs through developing various structural prototypes that fit load and support conditions within the desired volume setup. This generator allows to easily develop a wide range of structurally sound (abstract) designs that will be materialised only later on in the process when more architectural design criteria are taken into account (Fig. 2). This generator can be importantly influenced by an existing building if it determines the conditions (e.g. possible supports) of the prototype creation.
Structure Reuse (8 projects)
The ability to reuse structures in other constellations for different architecture projects, is a generator for these design processes. It requires the construction process to be reversible and the structural elements reusable (Fig. 6). This generator importantly determines the characteristics of the structural elements and their interconnection and as such the design outcome. These structural possibilities are explored, refined and/or adjusted, and form the building blocks of the architectural design. When connections need to be made with existing structures, it will influence this generator significantly.
Aesthetics; mixed (building dependent and independent)
Different from the above group of design generators developed within the framework of structural engineering, these generators are primarily developed within the framework of aesthetics. Even though only one type of generators is identified so far in this group with only limited project cases, it is believed that more generators are possible.
Structure Experience (5 projects)
The elements of a building identified as structural, can instigate specific experiences with the observer of that building. In these projects, the design is directed towards certain (intended) structure-induced experiences. This generator is developed by analysing such experiences in various existing or self-developed project cases by evaluating the observer experience of the designer self (Fig. 8) or by surveying the experiences of other (external) observers. The developed understanding of the relationship between a structure and its observer experience guides the designer in the creation of architectural form.