Creating an Injection Mold

I have attached a file which I wish to create an injection mold for. I need a split box to encapsulate the object and then difference the object from that. I thought I would create a bounding box around the object, split it, and then difference the object from the two boxes. I am unable to effectively difference the object however. It is a mesh from a scan so I thought there might be issues there, so I tried extruding curve from contours but that gave me really strange results. Any suggestions? Thanks.

Heres a link to the file

https://drive.google.com/open?id=0ByCV3xwTUvCPSHJUejBTS1Izck0&authuser=0

The easiest would be to just use meshes since you are starting out with a mesh. Do you control the production process of the injection mold? That is, do you know if the CAM program that will be used can make toolpaths from a mesh?

Yes. I will be using FDM to print from an STL

Not that it necessarily matters - I’m just being curious: are you 3D printing a plastic injection mold? What material will the end result be made of?

At any rate, since you can live with a mesh, just make a mesh box (command MeshBox) that is half the height of the model and then use the MeshBooleanDifference command to create the mold part. Repeat for the other half. Note that you will likely have to rotate the model so that you don’t have any overhangs in the molds - which might be tricky on a model like this.

Does that help?