Architectural Desktop is a true object-based CAD software package. It seeks to facilitate the creation of virtual building models from which plans, sections, and elevations can be extracted readily. The extracted drawings serve as two-dimensional reports of the live 3D model data ...

Explore the meaning of parametric design and object oriented CAD. Following the steps of a tutorial on the display system, we will learn how to display a single drawing model in many different ways, all serving varying architec- tural drawing needs. By exploring the Style Manager and anchors, we will begin to gain comfort with some of the critical conceptual underpinnings of the Architectural Desktop software package. Some key goals of this chapter are as follows:

• Understand objectified CAD
• Work with the display system
• Understand object styles
• Understand anchors
• Explore the Content Library

Creating models in Architectural Desktop is an exercise in practicing parametric de- sign. Parametric design refers to the direct manipulation of various object parameters available within each of the objects as design decisions are being formulated. Objects in ADT are programmed to represent the real-life objects for which they are named. All real-life objects have a series of defining characteristics that determine their shape, size, and behavior. To get a better sense of what these parameters might be, think of the characteristic to which you would refer if describing the object verbally to a col- league without the benefit of a drawing. Consider a door, for instance. In discussing a particular door needed in a project with the contractor over the telephone, we would rely on descriptive adjectives and verbal dimensions such as â The door is 3'-0" wide, 7'-0" tall. It is solid core and has a hollow metal frame.â Once we had settled on the door required and hung up the phone, we would then need to convey graphically in our drawing documents the decisions we had just made regarding that door (and any other like it.) In traditional CAD (AutoCAD), this would mean translating dimen- sions and materials into corresponding lines, arcs, and circles that represent the re- quired dimensions and materials in the drawing. In objectified CAD (ADT), these dimensions and other specifications are simply entered in a series of fields on forms that store the data for the object. This data remains accessible throughout the life of the object and the drawing. Therefore, the next time we phone the contractor and realize that circumstances on the site have forced us to spec a different door and size, rather than redraw the door and adjust the wall in which it sits, as we would in traditional CAD, we now simply re-open the data form for that door and enter the new values. Not only is the door itself updated because of this change, but the wall in which it is inserted is updated as well. This is parametric design. Object parameters are always available for editing; data never needs to be recreated, only manipulated.
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