[Richard]

Just a basic block displacement and precomp of geometry from high contrast basic rectangular forms for windows doors etc.

[eric nixon]

You would need to provide a nice quad based mesh for coversion to 'voxel' shapes, so it wouldnt be worth it most of the time, maybe theres a piece of geometry generating software / plugin which can build those block forms.

Basically this should reside in 3D workflow as a modelling issue. I guess Voxels are to limiting to become some kind of standardised useful format accesible to renderers.