real time mesh deformation with regards to environmental damage

Question

I would like to be able to add this feature to my tech demo. At the moment bullets hit the walls and little pieces fly out of them, as well as decals appearing on the walls. However, now computing power is good enough so that many games have destructible environments.

I would like bullets to shatter small surface segments off the wall, ideally the segments that fly off would directly relate to the hole that is left (though I don't even know if this is how it's done in commercial games)

How is this done? Are there simply a number of different meshes that are swapped out as and when objects are hit? I assumed that this would not be an accurate enough solution. Is real-time mesh deformation feasible and if so, how is it done?

Answer 1

There are two basic concepts:

1) Parallax mapping bullet holes (This is what Fear 1 used). It doesn't actually change any geometry, but due to shader magic it looks like there's a hole where you shot.

2) Actually breaking off chunks of geometry. The Unreal engine has something called the Fracture tool which helps author this content. I'm not sure how it works under the hood, but here's the documentation on how to use it: http://udn.epicgames.com/Three/FractureTool.html