How to bake normal map if the models intersect?

Question

I'm trying to bake normal map (highpoly to lowpoly).

I made a test scene with a simple high poly and low poly cube, but after baking I didn't see any details on the normal map, here is the screenshot:

However, after I reduced the size of the high poly cube so that only pieces with sculpting were outside the low poly cube it worked fine!

My question is: After sculpting, my model was slightly deformed. And when I am placing together the low poly and high poly models, the high poly model is slightly shifted outside of the low poly model. How can I get a normal map of the high poly model in this case (and not to get an empty normal map where the meshes intersect?)

I need to figure it out before Monday, so I would be very super for your help!

Answer 1

To bake from an object with is slightly outer of your lowpoly mesh, you need to increase the ray distance option in the bake panel:

Blender bake using a ray casting. If the ray distance is 0, the ray starts from the lowpoly surface. So, if this surface is inside the highpoly mesh, the ray meets nothing.

With a higher value for the ray distance the ray starts farther to the outside of the lowpoly so that it can hit the highpoly surface.

Practically speaking you may need to tune this value (not too high, not to low) so that the ray does not hit unwanted surfaces of the highpoly mesh.