Creating a negative shape from a mesh??

[thomas-buchan]

Hello 

I have a 3D scan which is saved as a STL (I've attached the file). 

I would like to make a shape that fits inside it, using the mesh as a work envelope so to speak but my experience with working with mesh's up to this point has been very limited. 

The scan is of the corner of a car dash, pillar on the left, glass on the top and i would like to fit an object inside that corner space.

It's not great quality as i'm not dimensional interested in it but i'm interested in the workable area within there roughly. 

How would i go about making a negative shape that fits inside the mesh? i did search for some help but i couldn't find any information on making a shape from the negative of a mesh.  

Any help is appreciated thank you. 

[etfrench]

You can use the mesh tools to cut this from another mesh.  You can create the other mesh by modeling a solid, then tesselating (convert to mesh) it.

[thomas-buchan]

Thank you for the advice, i'm making some progress. 

[thomas-buchan]

So I've got my two meshes on top of each other now, which tool would you use to cut them?

I tried Combine set on cut but it never seems to turn out very well.

It's very rough at the moment while i learn the process. 

Thanks

[etfrench · Accepted solution]

You may need to make your mesh a closed body in order to make the negative shape.  It should work like this:

[thomas-buchan]

Thanks for taking the time to put that up, it was very helpful. 

Closed the Mesh and it worked great.