||ARCAID?The ARChitect's Computer Graphics AID?is one part of a two-part research program at the University of Utah under the direction of David C. Evans. ARCAID is a specification for the organization of computer processes including data and procedures for the use of architects, engineers, and others in design. As the second part of this research C. Stephen Carr is developing the complex data structure which supports ARCAID. This data structure includes a graphics FORTRAN, a compiler-compiler, an associative memory, and a tree structure for organizing the data for a building scheme. ARCAID is an interactive computer graphics system relying on the Cathode Ray Tube (CRT) for feedback and a typing keyboard, stylus and tablet, trackball, and zoom pedal for input. The picture at the CRT is refreshed by a small computer, and manipulations of alphanumerics and graphic elements are handled by a large computer. ARCAID envisions the design of a building from first briefing and schematics through construction without the use of paper. ARCAID incorporates a computer graphics language called SPACEFORM. I t provides for graphic elements and procedures by which elements are manipulated. The basic graphic elements, "spaceforms," are built up from such primitives as points, lines, and surfaces. Basic spaceforms may be shaped and assembled for more complex (shaped) spaceforms and objects. Proposed manipulations include housekeeping, shaping, assembling, viewing, orienting, and miscellaneous manipulations. Spaceforms are topologically described with respect to geometry and at tributes. By geometric topology the corners, edges, and faces of objects are constrained to retain fixed relationships permitting rotations and other viewing manipulations thereby. By attribute topology the descriptions of objects are also linked to such at tributes as texture, color, weight, and the like.