Modeling 1: Polygons - An Introduction to Computer Graphics for Artists - page 84

Fig. 6.13 On left , two perpendicular reference cubes positioned to match the reference drawing.
At middle and right, how separate sections of illusion structure fi t together and their relationship
to reference cubes (Solution courtesy of Katharina Schütz)

6.5.5 Alignment Illusion Solution

The problem in this assignment is to work out how the parts of the structures
depicted in the drawing are attached. They cannot be attached as they appear to be,
so an analysis of the drawing must be made fi rst. One way to do this is to make a
drawing of a top view of the scene, with a rectangle to represent your camera. Draw
a straight line perpendicular to the camera in the direction of the scene. This is the
center of your scene. Draw other rays, and determine how they interact with scene
elements. You will fi nd that pieces that cannot be attached but appear to be, lie on
either side of rays projected from the camera as in Fig. 6.14 .

6.5.6 Block Out Scene

The illusion forces you to use objects of different scales that are not connected as if
they are the same scale and are connected. Because of this, you will need dimension
reference objects to build your model correctly. After the camera is set and you have
determined how the parts of the scene are broken apart, you should block out your
scene. To block out a scene is to create rough stand-in geometry to determine where
the major pieces belong and what size they should be.
If you have set your camera properly, this step should not be very diffi cult. It is
similar to adjusting the original reference cube, but now you will use smaller cubes