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

Disclaimer: The following could potentially be wrong:
As far as I know, all 3D Models are created in such a way that they don’t have thickness.
Basically all you model are the things visible to the player and only the outermost layer. The surface of the model is divided into smaller so called faces. These faces have an orientation (normals) which basically determines the direction it has to be viewed. This is especially true when used in videogames, since they only render the side you should look at, making the model see-through from the other direction.
However, unless anything went wrong, you should never see this. To model in a way, that accounts for mistakes made elsewhere is a bad Idea in my book, not to mention the extra work needed to make it and for the game to render it.

tl,dr: Models are paper thin because you only model what you can see and to save ressources.

Ps: To prevent such glitches you should work on the update-order (check beforehand if a transform is possible) and make the colliders big enough. Modeling with density wouldn’t prevent the issue and would probably lead to a black screen (within material there is little light).