I’ve learned that video game ‘clipping’ is caused by high velocity, thin colliders, and too-slow physics updates. Why are terrain surfaces in most 3D video games paper-thin? Why isn’t terrain given extra fill/thickness inside and under it to prevent ‘falling through the map into the void’?

Question

I could see why you might not want to fill under the terrain in a game that features things like underground caves, but thin terrain seems to be present in a huge majority of 3D games (even those without underground features) and is not engine-specific. Why is terrain almost always a fragile piece of origami that’s so easily punctured?

In: Technology

Answer 1

I feel like most answers here go into way too much detail compared to what is actually required to understand this.

The reason only the surface of the terrain (and other objects) is there is that it’s the only thing that matters. You only see the surface; you only interact with the surface. The volume below doesn’t matter to the player. So modelling it is a waste of resources, which are often scarce in computer games. Also, working with a volume is *way* more expensive than working with a surface.

Pretty much the only observable effect of this is the clipping you describe, which most games are able to work around easily enough.

Note that even for transparent objects (e.g. glass) only the surfaces are needed to create the image you see.

There is stuff that would need actual volume data, e.g. smoke, but it’s not usually done like that because it is too expensive; it is faked by rotating images or similar instead.