Computer Graphics Survey

Modeling a 3D Scene

Using Art of Illusion 1.7 on Macintosh Runtime for Java

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For the antiquarians in the audience, we have older versions of this tutorial, using:
| VectorWorks 8 | MiniCAD 7 | Strata StudioPro 2.5 | Strata StudioPro Blitz 1.75 |

Before beginning the project

Tutorial Goals

Since the 3D software marketplace is very fragmented, there is no single industry standard for 3D programs. Art of Illusion is an ideal training tool because it provides a broad cross-section of the features shared by all the major players. At the same time, it preserves a clean, standardized interface, unlike commercial programs which resort to quirky gadgets--making it hard to reuse what you have learned when you approach a new program.

While the program is simple to use, it is not simplistic. It can be used for serious work, as it has all the capabilities required for the complete 3D workflow: modeling, rendering, and animation.

In this first phase of our 3D project, we will use the most common modeling tools: we will start from flat 2D shapes, converting them to 3D using two techniques generally available in all 3D programs: extruding and lathing. Later we will work directly with basic 3D shapes called primitives, combining them using boolean operations and reshaping them through mesh editing.

After some initial setup, we can proceed to create the elements in our scene:

Initial Setup

  1. Reset the program to factory defaults by removing the file '.aoiprefs' (if found) from the Preferences folder inside System Folder.
  2. Double-click the Art of Illusion application icon to start the program
  3. A blank document window appears. It shows four views (Front, Left, Top, and the perspective from Camera 1) of your virtual workspace.
    New, Untitled document window showing four views
  4. Grid options dialog with Show and Snap checked
  5. the Front viewport zoomed to 10, with grid

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Lathed Pedestal

  1. the icon of the Approximating Curve tool, 2nd from the bottom in the right half of the tools palette Choose the Approximating Curve tool.
  2. the profile: half of a front view of the pedestal Working in the Front viewport, draw the profile for the pedestal (representing one half of a front view of the finished object) using the Curve tool in a connect-the-dots fashion. To give our pedestal a flat level top, the first two points at the upper end of the curve should align horizontally. The rest of the profile is up to you.
  3. When done drawing, leave the profile selected (red handles are visible at the sides and corners of its bounding box).
    the profile selected, and curve entry in list
  4. Choose the Tools-->Lathe command. The Lathe dialog appears, choose the settings as follows:
    Lathe settings
  5. The result is a symmetrical 3-D shape, with a circular cross-section, based on the 2-D profile you drew earlier.
    Four views of the lathed pedestal, new entry in list

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Extruded Logo

  2. the letter S just above the pedestal Working in the Front viewport, click the sequence of control points to create the shape of the letter. Double-click to set the last point, and a 'Curve 2' entry will be added to the Object List. Leave the curve selected.
  3. the letters S-A-M converted to polylines
  4. The result is a tubular 3-D object, with a circular cross-section, bent in the shape of the last 2-D profile you drew.
    Four views of the extruded letter, new entry in list
  5. If the object is not quite to your liking, it is easy to make changes to it: the Tube command we used is a simplified form of extrusion, sweeping a preset shape (a circle) along the selected curve. The advantage to this simplified technique is that the entire 3d object can be reshaped by modifying the few points that make up the curve.
    extruded letter reshaped in Tube edit window

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Boolean Subtraction Walls

  1. Cube settings dialog Using Object-->Create Primitive-->Cube, insert a box that will become the outside surface of the walls and floor slab of a simple building. In the dialog which appears next, enter a size large enough to enclose the entire scene. Assuming you sized objects roughly as shown in the previous steps, you can use these measurements:
  2. Repeat the same process to create a second, narrower and taller box (e.g., 14 long and wide, 16 high).
    the two intersectingcubes
  3. the green sphere and cross-arrows icon of the Move Object tool Next, choose the Move Object tool so that we can adjust the position of the cubes.
  4. Now drag up the taller cube (Cube 2), so that its bottom edge is above the bottom edge of the wider cube. The gap between the bottom faces of the cubes will become the floor slab of the building.
    both boxes, wireframe rendered, and properly positioned
  5. the dialog used to subtract the inner box from the outer one Solid modeling lets you create complex shapes by combining simpler ones. In this case, we will use the inner box to subtract (carve out) a cavity in the outer box:
  6. You have created in a single step the walls and floor of a room. Hide the objects 'Cube 1' and 'Cube 2', and you will see clearly the new object, 'Boolean 1'.
    the room, and its contents rearranged
  7. a few cubes driven through the walls Now you can cut your choice of doors and windows in the walls of the room by subtracting additional cubes, created either with the Object-->Create Primitive-->Cube command, or by drawing with the Cube tool. the blue cube icon of the Cube tool
  8. windows and doors in the walls, where the cubes used to be Complete the room with Boolean subtractions:

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Triangle Mesh Roof

  1. We'll use another cube as the initial shape of the roof.
    the room, and its contents rearranged
  2. Make sure the new cube is still selected, then change it to a format you can reshape using Object-->Convert to Triangle Mesh.
  3. With the cube still selected, use Object-->Edit Object to open the Triangle Mesh editing window
    top points selected in Mesh edit window
  4. Delete the selected points (and the polygons defined by them).
    top points and polygons deleted
  5. Select the top vertices of the triangles.
    current top points selected in Mesh edit window
  6. Bring together the selected points at the center of the workspace.
    top points converged, polygons joined
  7. Check all views to get a good idea of the 3D nature of the scene you created.
    the completed building
  8. Use File-->Quit to exit the program. Make sure your file is saved so you can continue working with it during the next session.

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Information specific to the ACG Lab


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