Voxelizer Plugin uses Physics.Raycast method to transform any 3D model into a set of voxels, i.e. cubes. Voxels are created at edges of a model and optionally also inside it. Voxels are rendered in a single draw call providing they are of the same size, same or shared material and the texture has no transparency.
More details can be found in Voxelizer_ReadMe.pdf.
Voxelizer was developed in Unity ver. 4.7.2f1.