Success, I have polygon reduction running ontop of marching cubes. I’m collapsing edges based on minimizing the angle between triangle normals. The algorithm is currently running a little slow to use real time, but I’ll optimize it once I have the features and look I want.
Next I’m going to work on incorporating polygon reduction into scaling the terrian at a distance (LOD). My goal is to be able to render mountains far away while still allowing for concave terrian. Thankfully it’s easy to run marching cubes at different scales.
The left side of this image has 1⁄4 as many triangles as the right. The image is lit using vertex normals and random gray scale values for the triangles.