Trouble interacting with an imported .OBJ

[karl]

In the attached file, I've imported a .OBJ of a round disk with a hole pattern in one side.  The other side is a flat solid face.  I'd like to cut a hole in this face a little smaller in diameter than the disk.  I was unable to create a sketch on the face, so I created an offset plane, sketched the circle, and tried to extrude it to cut through the face, but this generates the error, "No target body found to cut or intersect."  Do I have to somehow convert the imported .OBJ before performing operations on it?  Thanks for any tips.

[jeff_strater · Accepted solution]

OBJ is a mesh format.  Operations such as cut only operate on solid bodies.  

You can turn this into a solid body, in the Mesh toolset, using the Convert Mesh command:

You will likely have to use the "faceted" option for this mesh:

however...  This is not a highly recommended workflow.  Mesh geometry is inaccurate, and faceted.  So, depending on what more you want to do with it, you may be able to get away with a converted mesh to solid, but the experience might be slow (this produces a complex solid body), and the results will be less than ideal.

[laughingcreek]

please note what jeff says in the last paragraph of his response.  converting a mesh directly to a solid generally not a good idea.

here's another workflow that works well when combining or subtracting simple shapes for a mesh.  convert your solids to be combined or subtracted to a mesh instead, and use the combine tool in the mesh environment.  I've attached your model with an example of what I'm talking about.

if this obj was a quad mesh, there is another workflow that might also work.  you would have to deselect triangulate mesh on import in the preferences before importing the obj.  but for what you described you want to do, I think the attached approach is probably the most appropriate.