inverting a model quickly?

[tony978]

I was wondering if there was a quick way to invert a complex model to make a mold ? The model is a mesh witch makes things hard I think .

[chmillman]

There may be a few... Yes, the fact that the model is a mesh will be difficult for Rhino. You can try to subtract it directly from a block (surface or mesh) with MeshBooleanDifference. If that fails, you can try manually deleting the open face (I assume it is planar), create an open mesh box, dupe the edges of the mesh box and the object, use the PlanarMesh command on the resulting polylines, and then join the 3 meshes to create one closed object. There are several other ways to do this, but without the model, it's hard to know which is the best. --ch

[tony978]

Thank you for your reply I did try a MeshBooleanDifference.
In rhino and in grasshopper . The model is organic textured and
Medium high detail . Then MeshBooleanDifference in rhino got stopped after 9 hr the model was scaled to 8x13 . Do you think it might be the scale of it that
Would be the problem , I am running rhino 4 sr8 which is 32 bit ?