Best way to split complicated model to make a mold?

What is the best way to split this model in 2? In need to make two halves of a mold, but the model is organic and I need to place the cutting line on very specific point.

Rhino is a bit notorious when it comes to splitting meshes in my opinion, anyone know of a better software to do this ?

did you try any Rhino tools already or are you just generally looking for alternatives?

I’ve tried the usual suspects: MeshSplit, Meshintersect, Meshboolean split.

But my main problem is getting a nice line on the surface of the mesh. I know there is a tool to draw on a mesh surface, but it is difficult, because this tool snaps on every vertex your mouse hovers over, so it’s quite difficult to get the line exactly as I want

are you talking about PolylineOnMesh? you can simply deactivate vertex snapping it then will be as accurate as you draw it without being disturbed.

mesh boolean stuff indeed often makes trouble, my workaround is to convert the mesh with MeshToNURB to a polysurface and then use the regular boolean. that usually works. i must point out the success of this also entirely depends on the quality of the mesh, if it is not a solid closed mesh or has nonmanifold faces joining, that will cause hick ups so cleaning up your mesh is a must. sometimes if the mesh is dense it might need a few moments to think.

if that does not work post your file and somebody can try to get a working method.

Hi Simon -

If you are running Rhino 7, you could use the DraftAngleAnalysis command to create the “mid draft curve”.

FWIW, I suspect that, with a shape like that, you’ll have undercuts and it won’t be just a matter of making 2 halves.

this mesh is going to need a considerable amount of clean up in order to be useful for mold making. the “chatter” on it’s surface will make your life miserable.

I’d quadremesh this part, and convert it to subd then to nurbs and make your parts off the nurbs model.

can you give a little more info about what this is and what you are trying to do with it?