3D Graphics in The Sims 2

Object Complexity

Incongruously, the three-dimensional word of The Sims 2 will tend to drive us toward less complex objects.

When we have a fixed viewpoint we can add as much detail as we can cram into the available pixels. In a three-dimensional world the more planes and edges there are in an object, the more CPU time it takes to render it. Complex objects can also result in very large files.

As a three-dimensional object the Moon Sims Moon Rover shown above takes almost a minute to render on a high-end CAD machine. We got away with this in The Sims because all the rendering took place off line. The vehicle's designer, Boris Rubanovich, rendered each of the views in the standard Sims views and then Dincer Hepguler used those sprites to convert it into an object for The Sims.

This thing would bring The Sims 2 to a dead stop. Maxis art director Dave Patch says that face and body skins in The Sims 2 have about 1200 vertices each, not including the hair. In contrast, this moon rover has hundreds of thousands of vertices. We will have to design a much less complex vehicle before you see any moon rovers in the new game.

The same goes for any other object in the game. Our major challenge will shift from fighting with those furshlugginer z-buffers to figuring out how to represent what we want with the minimum number of surfaces.

We will also be learning a whole new set of techniques for representing curved surfaces where sharp edges meet so that rounded things still look rounded without having to invest thousands of facets in a single teacup.

The glasses in this detail from the back-deck scene are an example. Curved surfaces are especially a problem in designing 3D objects because it takes so many facets to represent the surface. Instead of being perfectly cylindrical, these have twelve flat sides. That is quite sufficient to do the job. Except in a very close-up view like this, you would never notice. Even in a close-up view they would be moving in the game, so you still might notice the actual shape of the object.

If you look closely you can also see that the glasses are partially transparent. This is most noticeable in the glass held in the juggler's right hand, where you can see the straps of her bikini showing through the glass. Minimizing the number of polygons is especially important in transparent objects because more polygons means more ray-tracing and reflections have to be calculated.

3D Graphics in The Sims