Introduction to 3D Using Strata - Page 4

Though different 3D packages vary in terms of the complexity of the working environment, the common denominator among all of them is that they are complex. There is no way of avoiding it. The challenge of all 3D art — and therefore of 3D tools — is to represent three-dimensional objects in two- dimensional space. In everyday life, this illusion is taken for granted. You see images in film and television and you assume that they have depth, even though the depth is not explicitly visible. Creating 3D models and animations, by contrast, requires that you be able to explicitly define each point in a 3D scene. The first requisite for doing this is understanding how you might represent 3D objects in three coordinate planes or axes, and this is a matter of just having that part of the brain switched on. If you are comfortable with the concept of points existing in a three-plane coordinate system, all that remains is to figure out how your software package represents that system and how to move around within that system. This part of the chapter attempts to acquaint you with Strata's basic methods in this regard.

Primitives

Primitive shapes, or primitives, are the shapes that are built into the 3D software as part of the toolset. There are different numbers of primitives available in each 3D package. The free Strata 3D package includes six primitives, as shown in the next illustration. They are, left to right, top to bottom: sphere, cube, cone, rounded cube (called chamfer cube elsewhere), cylinder, and pyramid.

The easiest way to place one of these shapes is to click on the primitive on the toolbar and then drag over the desired area on the stage. However, as with everything in 3D, there are many options for how to do this. A primitive that has variable parameters, like the rounded cube, can be adjusted before you draw by double-clicking on its button in the toolbar before you place the primitive on the stage. Figure 20-1 shows a dialog for the rounded cube where the corner radius is set to 20% instead of the default 50%, with the resultant cube in the background.

Most people like to draw primitives one or two dimensions at a time. You can do this by selecting a primitive in the toolbar and then single-clicking on the stage to start drawing the base of the primitive object. After you click a second time, you will begin drawing the height of the object. The third click terminates the drawing at the current mouse position.

Another option you have with drawing primitives is the Constrain to Rectangle option. To constrain the primitive to equal dimensions in each direction, hold down SHIFT as you draw. This works exactly like it does in 2D graphic art software. The last basic option for drawing primitives is drawing from the center point instead of the corner. Just as you would suspect from your experience in 2D art programs, the ALT key activates this option.

At this point, it is informative to note the exceptional level of precision and the number of options available for something so simple as drawing primitive shapes. In most 3D packages with a lot of features, there are many ways of performing any given task, each with its own advantages. Learning the exhaustive list of options for each task is part of becoming proficient in a 3D tool. Precision is much more important in 3D art than in 2D, since everything is interrelated.

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