Parametric and Form finding Techniques in Architecture
Introduction
Ugail (1999) stated parametric design as “The basic approach is to develop a generic description of an object or class of objects, in which the shape is controlled by the values of a set of design variables or parameters”. It is accepted as the General identification of parametric design. Through out this paper, it aims to provide a vista of Parametric and Form finding Techniques in CAAD domain. First part of this report is a brief review focusing on the roles of this two. After that, both of their application in the future will be further discussed.
The role of Parametric Design in CAAD
Visual arts and music have a long history of exploring algorithmic form generation. Music art has been largely engaged in the development and deployment of sound producing algorithms [1]. Similarly algorithmic generation of images has been a central theme in visual art. Although algorithmic form generation has certainly had a presence in computer-aided architectural design, it is fair to say that other interests have taken a more prominent position.
Parametric design was first used in aero, vehicle and product design industries. It has been introduced into the architectural practice during the past few decades.
As Mark Burry (2002) stated, parametric design was born with many virtues: first, it gained efficiency for both designer and company; second, it provided opportunity to experiment designs in real time.
As the latest development in CAD software, parametric design refers to the inclusion of parametric data embedded within 3D objects. This type of software (examples: Autodesk's Revit, etc.) uses a revolutionary user interface in which the designer, instead of drawing lines, arcs, etc., as in "traditional" CAD software, inserts pre-drawn components, such as doors, windows, walls, etc. to first construct a 3D model instead of a 2D drawing. In some software in this category, the opposite is done: a 2D floor plan is drawn, and the 2D elevations, sections, details, schedules, and 3D model and rendering are all automatically generated from the floor plan as it is created, in real time. It can be done either direction in some other programs.
Parametric design provides a family of electronic prototyping with dependent variables in a model to variations in specified parameters. The parameters are not just numbers relating to Cartesian geometry[2], they could be performance-based criteria like light levels, structural loads, or even aesthetic principles. In the case of Cartesian geometry, the parametric design is referred to as ‘associative geometry’.
All parametric operations are linked together in some declared relationship, as simply insert in the parameters whose constraints are declared early in the design process either by the software engineer or the designer himself. If a model suffers from over-constraint in relationships, subsequent design decisions might be invalidated simply through the inability of the regeneration process to comply with conditions set by the designer earlier on.
However, as many hi-technologies did, parametric design also had some limitations, such as relatively high cost of the packages and introduces an implied design process that has to be followed step by step. Over the years, the design process and how technology is used at Gehry Partners hasn't changed very much. However, the technology itself has dramatically improved, which makes the interaction with it less onerous and a lot more pleasant. Parametric software is now more affordable. (For example, CATIA, it runs on the Windows platform, and the latest version v5 has an improved parametric engine and better visualization capabilities, all of which assist the workflow tremendously.) Similarly, the physical modeling process has also benefited from rapid prototyping techniques such as laser cutting and 3D printing. However, the amount of effort that goes into this modeling has not changed significantly.
Potential
• Methods for Object Representation in a computer graphics environment, Geometry and topology components are clearly defined: i.e. Surface parametric patches
• Easy to carry out a routine design process by parametric design
• Reproduces a set of potential solutions for consideration. Especially for the prototype creation. Known as a variant programming. It provide possible solutions for an Innovative design
Limitation
• Lake of relationship between objects;
• Difficult to deal with Top-down design or Conceptual design which refer to an optimize solution.
Future
To go beyond parametric design, Developments were encouraged. Generative systems are a well-established theme in CAAD, such as:
• Constraint based design: An extension of parametric design aimed at overcoming its deficiencies. Relationships are viewed as reversible.
• Shape grammars: a semantic model with a compressed representation of architectural form.
• Evolutionary architecture: genetic algorithms.
However, algorithmic form generation has largely remained the province of academic investigation, perhaps because of the level of technical expertise it has required.
As Birger Sevaldson (2002) mentioned in his work, based on techniques or found concepts different distinctive types of computer use are sorted into categories. Many of the categories are not so clearly limited and their borders are blurry. The most important aspects are the techniques. But the categories are important in relating the techniques to each other.
Start info | Processing | Tools | Technique | Category | Result | Projects |
Primitive geometry | Manual geometrical mani- pulation | Splines-based surface modelling software (Rhino, Alias) GUI and mouse-based displacement of CV | Dragging, rotating, scaling of one or groups of CVs | Mouse based modelling [3] | Work-process close to traditional design work | Numerous design projects. |
Primitive | Sculpting | Sculpt-tool Maya sculpting, Freeform Scanning software | Sculpting with dynamic cursors on surfaces or with special force feedback devices, | Mouse- (and other input devices) based sculpting | Work process that simulates traditional design process with physical models | Small Formations |
Site material or principal start conditions
| Simulation | Simulation software CATIA modules, FEM analyses urban simulation etc scientific simulation and visualisation software Weather forecast | Enter start conditions, run simulation. visualisation of results | Parametric design, animation -based technique[4] | Models that predict real life behaviour. Models can inform design process | VIZ scientific visualization tool Form Finding Modul IT-master |
Parametric engine set-up | Altering the parameters | Parametric CAD software, other software, Processing | Altering constraints and parameters, Scripting own software Programming in Processing | Parametric design | Models that allow for easy changing within the logics of the parameters. Investigation of many instances, complex relations. | ENØK, ASTRA Hybgrid Motion Graphics in IT-Master, Casey Reas |
As an advanced design and representation methodology with efficiency, more important, not too expensive; parametric design will not merged. But its borders with other methodologies will fade. That means, it will not be so special, just a daily thing.
Reference
Kolarevic, B. (ed.) Architecture in the digital age: design and manufacturing.
Lindsey, B. (2001) Digital Gehry: Material Resistance, Digital Construction, Birkhäuser
Phiri, M. (1999), Information Technology in Construction Design, Thomas Telford, London
Schmitt, G. (1999) Information Architecture: Basis and Future of CAAD, Birkhäuser
Sevaldson, B. (2002) Ways of Working. Systematising Creative Computer Use Thomas Telford, London
[1] Computer music, from the early days in 1955, Lejaren Hiller, working with Leonard Isaacson at the University of Illinois at Urbana-Champaign, began a series of experiments in computer-automated musical composition. In 1957, they finished the 'Illiac Suite' for string quartet, the first substantial musical composition created with a computer.
[2] In 1619, as part of the great illumination that inspired Descartes to assume the modest chore of reforming philosophy as well as mathematics, he devised “compasses” made of sticks sliding in grooved frames to duplicate the cube and trisect angles.
[3] Mouse-based modeling and sculpting is when there is an analogy between the physical movement of the input-device and the altering of the digitally represented geometry.
[4] Animation based techniques are most often crossover categories that can contain elements from parametric design, simulations or mouse-based modeling. But animation is so central in these new techniques that it appears as a category. When the animation process is central a technique will fall under that category.
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