This software allows you to transform your solid in a very interesting way.

You start with a simple full shape. In that case it was an egg with a hole at the top.

The soft projects a pattern on the enveloppe then it gives the projection a thickness to make a solid shape out of it. That's what you see in the picture. Afterwards it re-meshes the result to make it printable.

That's the general idea. Now I need to understand better some of the parameters. Also, be prepared : I don't know if meshmixer's algorithm is not optimized enough or if it is due to the complexity of the thing but I got frequent warnings saying it would require 2G+ of RAM for a transformation.