birth voxel and shell

[nayan]

Ah, I see what's happening.

By default, to speed up sub-element processing, the Birth Voxels operator splits up a mesh and processes its elements separately. Normally this makes it run faster on complex meshes but in your case, since the inside/outside are each independent surfaces, it's splitting up your shelled torus into two distinct non-shelled toruses and then filling them separately...which is why you're losing the holes. In the next build I will make element splitting optional, allowing you to get the shelled result in your scene.

thank you