How to use Displace and Solidify modifiers to produce constant thickness

Question

I'm modeling an insect carapace with indentations for 3D printing using the Solidify and Displace modifiers, and am struggling to produce a dented surface with a (nearly) fixed thickness.

Indentations are generated using a UV texture and Displace. Using the Solidify modifier before Displace makes indentations on the inner surface opposite the outer surface, producing thin areas incompatible with 3D printing. Putting Displace after Solidify predictably produces inverted mushrooms around each indentation.

What I want is to have indentations on the outside and bumps on the inside, producing a constant thickness. Failing that, I'd be happy with a means to suppress displacement on the inner surface.

I know of one "solution" I've used before, which is to apply Solidify, UV unwrap, and texture only the outer surface. However, this considerably reduces subsequent editing flexibility. Is there a way to order/tweak modifiers (or use an alternative strategy) to get the desired result?

Answer 1

You can use custom vertex groups in the Solidify and Displace modifiers in order to keep the inner surface intact.

First add a vertex group to your mesh.

In the solidify modifier, expand the Output Vertex Group foldout, and set the Shell group to be your new vertex group.

Also, in the displace modifier, set the vertex group field. You might need to invert the effect with the double sided arrow next to the field.

Result (with a subdivided plane for simplicity)

On Suzanne (probably not the best model for that since there is a lot of mesh intersection but I hope you get the point)