"How are 3D graphics rendered and made?"

Submitted by: Chris Trinh

Answered by: John Anderson (3D artist, Sierra On-Line)

"Well, there are a variety of methods to create 3-D graphics. There are at least 5 major programs used by artists in the world of 3-D. Some are called 'spline based' modelers, which create a form out of a series of curves. 'Patch' modelers create models out of flat grids which are manipulated by the artist. And we here at Sierra use a program called 3-D Studio Max, which creates models out of 'primitives'.

"Primitives are just basic shapes that the computer creates for us -- spheres, boxes, cones, etc. We then twist, contort, cut and paste these shapes into the form we need. Some programs allow you to build a clay model and then 'scan' it into the computer using a special tool, so that you can achieve more organic-looking shapes. 3-D graphics are all based on math and geometry. Therefore most things that come out of a 3-D program have a tendency to look very stiff or boxy, because the computer calculates the geometry too precisely. So the more organic-looking model you can make, the better off you will be.

"After you have built a model, you apply textures to its surface. Again, there are many methods to do this. If you just want a part of the object to be blue, you simply select that object and apply one of the many pre-generated color maps to it. If you want it to have a specific design, you can draw that design in a paint program and then apply it to the model. Applying a texture in this way is like putting on a shirt with no tag. You just put it on and then rotate it till it fits. After this, you set up your lighting source and specify the direction from which it comes and how bright it will be.

"Once all these things have been set, you ask the computer to render a complete 2-D representation of all the information you have given it. When (not if) it comes out wrong -- because you didn't set things correctly -- you adjust all of your variables and render again.

And again, and again..."

Read more questions and answers!