When I saw this tutorial on Greyscalegorilla, it occurred to me that although I liked the results a lot the process of sculpting and posemorphing would be a bit too unflexible for my needs. And of course it would also be too tedious for a lazy nerd like me to manually sculpt dents. I was already trying to figure out a procedural approach for this dented look.
What I came up with is relying heavily on Houdini’s excellent implementation of VDBs. VDBs are a really fast representation of voxels. Voxels are for 3D the same as what pixels are for a 2D image. Think of them as tiny cubes. Each voxel can store a Value. In our case the distance to a surface. If a voxel is on the outside, it will store a positive distance towards the surface. If a voxel is on the inside, it will store the negsative distance towards the surface. If we want to convert a volume containing voxels to a surface (polygons) we simply have to find out where the volume’s voxels have a value of 0. This is called an SDF, a signed distance field.
Enough stuff about the theory of voxels in Houdini. Let’s get building!