Mesh Surface to solid Mesh with Grasshopper

[fpoll (FP)]

I want to transform a mesh surface to a solid mesh with defined thickness for 3d printing of image lithophanes. Using the grey values of images I created a mesh surface like shown below:

Now I want to add sides and a bottom like marked in the next image:

So far I only managed to get solids for lithophane printing with the new ShrinkWrap function of theWIP-Version of Rhino, but I’m looking for a pure grasshopper solution.

I guess there is a way to create the missing box sides with grasshopper, but currently I have no idea how it can be done cleanly.

I’m looking forward to any tips on how to approach this problem

[martinsiegrist]

You can create a bounding box around your mesh, scale it so there is a good intersection and then subtract the mesh with the normals flipped from the box.

mesh_difference.gh (46.6 KB)

[fpoll (FP)]

That works perfectly and fast, thank you very much!