I am in the process of developing a Minecraft-like world where the terrain is divided into voxels. However, I would also like for unstable configurations of landscapes to collapse predictably. For example, an overhang that is too heavy would fracture and break off at 'high stress' voxels, as would a pillar formation with an asymmetrically eroded base. I was thinking about adding a 'stress vector' field to each voxel in the terrain, and doing the following (pseudocode):
foreach voxel in terrain
foreach neighbor in voxel.neighbor_voxels()
if magnitude(voxel.stress - neighbor.stress) > stressThreshold
But the problem is that I don't know how I would go about calculating these individual stresses. Is there some kind of FEA-based algorithm specialized for voxel discretizations that I can use to calculate the stresses on a per-voxel basis? Or am I approaching this all wrong and there's some other way to do this?