Shape computations without compositions

Parametric CAD supports design explorations through generative methods which compose and transform geometric elements. This paper argues that elementary shape computations do not always correspond to valid compositional shape structures. In many design cases generative rules correspond to compositional structures, but for relatively simple shapes and rules it is not always possible to assign a corresponding compositional structure of parts which account for all operations of the computation. This problem is brought into strong relief when design processes generate multiple compositions according to purpose, such as product structure, assembly, manufacture, etc. Is it possible to specify shape computations which generate just these compositions of parts or are there additional emergent shapes and features? In parallel, combining two compositions would require the associated combined computations to yield a valid composition. Simple examples are presented which throw light on the issues in integrating different product descriptions (i.e. compositions) within parametric CAD

Analysis of shape grammars: continuity of rules

The rules in a shape grammar apply in terms of embedding to take advantage of the parts that emerge visually in the appearance of shapes. While the shapes are kept unanalyzed throughout a computation, their descriptions can be defined retrospectively based on how the rules are applied. An important outcome of this is that continuity for rules is not built-in but it is "fabricated" retrospectively to explain a computation as a continuous process. An aspect of continuity analysis that has not been addressed in the literature is how to decide which mapping forms to use to study the continuity of rule applications. This is addressed in this paper in a new approach to continuity analysis, which uses recent results on shape topology and continuous mappings. A characterization is provided that distinguishes the suitable mapping forms from those that are inherently discontinuous or practically inconsequential for continuity analysis. It is also shown that certain inherent properties of shape topologies and continuous mappings provide an effective method of computing topologies algorithmically.Comment: 23 pages, 6 Figures, 6 Tables. Research Report, 2020, MIT. Preprint of Journal Article (2021

Making grammars: From computing with shapes to computing with things

Recent interest in making and materiality spans from the humanities and social sciences to engineering, science, and design. Here, we consider making through the lens of a unique computational theory of design: shape grammars. We propose a computational theory of making based on the improvisational, perception and action approach of shape grammars and the shape algebras that support them. We modify algebras for the materials (basic elements) of shapes to define algebras for the materials of objects, or things. Then we adapt shape grammars for computing shapes to making grammars for computing things. We give examples of making grammars and their algebras. We conclude by reframing designing and making in light of our computational theory of making

Defining Rules for Kinematic Shapes with Variable Spatial Relations

Designing mechanisms can be a challenging problem, because the underlying kinematics involved are typically not intuitively incorporated into common techniques for design representation. Kinematic shapes and kinematic grammars build on the shape grammar and making grammar formalisms to enable a visually intuitive approach to model and explore mechanisms. With reference to the lower kinematic pairs this paper introduces kinematic shapes. These are connected shapes with parts which have variable spatial relations that account for the relative motion of the parts. The paper considers how such shapes can be defined, the role of elements shared by connected parts, and the motions that result. It also considers how kinematic shape rules can be employed to generate and explore the motion of mechanisms

Exploiting lattice structures in shape grammar implementations

The ability to work with ambiguity and compute new designs based on both defined and emergent shapes are unique advantages of shape grammars. Realizing these benefits in design practice requires the implementation of general purpose shape grammar interpreters that support: (a) the detection of arbitrary subshapes in arbitrary shapes and (b) the application of shape rules that use these subshapes to create new shapes. The complexity of currently available interpreters results from their combination of shape computation (for subshape detection and the application of rules) with computational geometry (for the geometric operations need to generate new shapes). This paper proposes a shape grammar implementation method for three-dimensional circular arcs represented as rational quadratic Bézier curves based on lattice theory that reduces this complexity by separating steps in a shape computation process from the geometrical operations associated with specific grammars and shapes. The method is demonstrated through application to two well-known shape grammars: Stiny's triangles grammar and Jowers and Earl's trefoil grammar. A prototype computer implementation of an interpreter kernel has been built and its application to both grammars is presented. The use of Bézier curves in three dimensions opens the possibility to extend shape grammar implementations to cover the wider range of applications that are needed before practical implementations for use in real life product design and development processes become feasible

Spatial layout planning in sub-surface rail station design for effective fire evacuation

The London Underground network is a crucial part of the transportation system in one of only four ‘Alpha’ world cities. The other three – Paris, New York and Tokyo – also have such sub-surface railway transport systems that may benefit from this shape grammar station design process in a future research proposal. In London’s case, the passenger flow rates are the underlining factor in sizing infrastructure where passengers have access – it is therefore this criterion that provides the basis for the shape grammar formulation for the largest, oldest and one of the most complex underground systems in the world. The research aims to improve passenger fire evacuation times, with due cognisance of the growth of numbers using the system, and its present susceptibility to terrorist attacks taken into account. The proposed shape grammar approach will provide for generation of spatial layouts, based upon visual rules of shape recognition, replacement / union, their connectivity and spatial relationships. The paper concentrates on definition and implementation of novel shape grammar design rules that incorporate station planning design knowledge, and in particular also discusses designers’ fire risk assessment approach and related knowledge that is also needed to produce credible station design solutions. Development, to date, of the proposed artificially intelligent CAD environment is also described along with parallel theoretical research. The proposed CAD interface provides familiarity to the designer and avoids incompatibility issues regarding drawing exchange format between various software systems. The shape grammar layouts produced will be tested in SIMULEX, a commercially available evacuation package, and be compared against ‘traditionally’ designed layouts to demonstrate improvements of preliminary ‘reference’ designs, which follow the standard London Underground design process as a later stage of this research

Tools for the co-designing of housing transformations: A study on interaction and visualization modes

In this paper we present and assess tools for visualizing architectonic modifications of existing housing in co-design projects with inhabitants. These tools should enable inhabitants to explore and understand design variations of alterations of their houses. This contribution is part of ongoing research on the use of artificial realities for supporting the transformations of existing housing in architectonically responsible ways. Such transformations may be needed after the delivery of housing, say after five years or later, due to changed regulation, the need of updates or changed living conditions of inhabitants. For arriving at architectonically responsible transformations, we use shape grammar system for defining possible modifications of the housing. For empowering inhabitants to understand and explore these modifications to their housing, we develop a transformation grammar tool—MyChanges—to visualize the modifications by three visualization modes, from fully immersive to non-immersive. Interviews and tests with real inhabitants were performed, and preliminary conclusions show that a tool like the MyChanges would have a good acceptance among inhabitants.info:eu-repo/semantics/acceptedVersio

Formal descriptions of material manipulations: an exploration with cuts and shadows

Shape computation in design is never purely limited to visual aspects and ideally includes material aspects as well. The physicality of designing introduces a wide range of variables for designers to tackle within the design process. We present a simple design exercise realised in four stages where we physically manipulate perforated cardboard sheets as a case to make material variables explicit in the computation. The emphasis is on representing sensory aspects rather than easily quantifiable properties more suitable for simulations. Our explorations demonstrate the use of visual rules to represent actions, variables and form as well as how to control the variables to create new results, both desired and surprising, in materially informed ways