COMPUTER AIDED ARCHITECTURAL DESIGN
ARCH 6410/3410: SEPTEMBER 15, 2011

Exercise 3: Solid Modeling & Transformations, Introduction to Surfacing
Due: October 14, 2011

This assignment will introduce some of the techniques and concepts of three dimensional modeling. It is probably the most difficult assignment for the semester in that you will undertake 3D modeling with an advanced use of construction planes for the first time. Later on during the semester we will be revisiting 3D modelng concepts with increasingly more advanced technology options. Correspondingly, you will redevelop the geometry in your model with greater detail in later exercises.

Within exercise 2, we examined symmetry operations in two-dimensional wireframe modeling. Now use the wireframe model as a generative basis for solid modeling techniques. The primary focus for this exercise is 3D geometrical primitives and solid modeling. The goal is to produce a slightly detailed massing model. Going beyond solid modeling, 3D surfacing and parametric 3D modeling will also be introducted in the workshops over the next several weeks. For this exercise you will likely want to integrate some surfacing techniques at a preliminary level.

NOTE: Start on this assignment early and work on it consistently over the next several weeks. Seek out interim feedback on your progress or on technical questions. That is, work incrementally over the period of time prior to the due date rather than attempt to do the project in one later marathon effort.

Four Stages In The Development of The 3D Model

1. First, build a 3D wireframe model that may consist of lines, arcs, circles or any other graphic primitives that may serve as the basis for generating the solids. Use the Accudraw Construction System in order to facilitate the 3D construction of your wireframe model as described in Microstation's help documentation and the workshop.
2. Second, use the wireframe as a direct basis for creating primitive solid elements, such as projected solid walls and similar architectural elements. Or, using the wireframe modeling as a geometrical point of reference only, create more directly solid model primitives such as spheres, boxes, and cones more directly in the construction of the three-dimensional model.
3. Third, apply Boolean commands to the primitive solids so as to develop more refined 3D shapes. (see 3D Design and Modeling elements in the Microstation User's Guide, and also the WWW handout on Solid Modeling). Note once again that you should not attempt to develop the 3D model in great detail, but only to develop a general representation of its massing and geometry.
4. Fourth, where applicable and more effective than the use of solid modeling elements, introduce surfacing techniques to the construction of the 3D model.

The following three figures show a rogh development of Mies van der Rohe's German Pavilion on the computer. Figures 1 and 2 are of the plan and elevation such as you might have produced in exercise 2. Note that different architectural elements are grouped together by color and level so as to make the drawings more coherent. Figure 3 describes a "wireframe" rendering of the projected solid geometry of the German Pavilion in three dimensions. Figure 4 describes a simple shaded image of the solid elements, such as the "solids of projection" discussed in the Microstation User's Guide.

Figure 1: Plan Wireframe of Mies van der Rohe's German Pavilion.

Figure 2: Elevation Wireframe of German Pavilion.

Figure 3: Isometric Wireframe of German Pavilion.

Figure 4: Simple Shaded View of German Pavilion.

Considering Geometrical Order in Your Approach

As you had done in exercise 2, re-examine the work of architecture or design in terms of its geometrical elements and order. For example, take note of what symmetries may be evident. It may be possible to use mirror, rotate, and copy operations within the CAD system to revisit these symmetries within your 3D model. Attempt to understand your project as a composition of abstract geometrical forms and consider how you might approach the modeling process as one of a sequenced ordered assembly of Boolean operations. That is make note of what symmetries may be present as a basis for move, copy, mirror, rotate and scale operations and consider the use of union, difference and intersection operations. Use layers as a way to further give organizational clarity to geometrical elements. You may optionally choose to explore the application of "cells" (also referred to as instantiated figures) to deal efficiently with repetitive components which vary only in scale.

In order to get a feeling for how to schematically view the geometrical organization of a work of design, you may wish to browse through the Precedents in Architecture textbook by Roger H. Clark and Michael Pause as cited in the course syllabus. The textbook is perhaps oversimplified in its descriptions of some buildings. However, it develops an interesting system of analysis in taking on some geometrical organizing principles such as "Plan to Section", "Massing", "Unit to Whole", "Repetitive to Unique", "Geometry", and "Symmetry", suggests approaches to viewing a work of design schematically that may be used as the basis for a modeling exercise.

Do not attempt to build a completely detailed model, as this is really unnecessary to the objectives of this exercise, may be time consuming and inefficient. Rather, take on an aspect of your case study and develop it abstractly with an emphasis on geometrical composition. We will later learn more efficient ways of handling details through such techniques as advanced surfacing and texture mapping.

Submit a Microstation model file (.dgn) showing the basic compositional elements of your design object. Provide a short assignment description via email that corresponds to your drawing and describes important levels, views, problems, and anything else of interest.

Place your finished drawing file in the subdirectory "submit" that you used for exercise 2, then send email to ejmark@virginia.edu as well as the TA for your section.