how to convert imported STEP solid to a real solid?

[modelguy]

I have a large STEP file to import into Cadkey 19. It comes in fine 35+meg, but when I cut it to take out a part to make a STL model, it is thin surfaces. I converted the whole thing to surfaces, and created surfaces where the cut planes are but it will not reconvert to a real solid. (Invalid model)
I tried reducing tolerances, but that did not work. The STEP file weas created out of CATIA. I need to subtract some cylinders for countersinks and bolt holes. I am stuck.

 

[moldcore]

Did you get this resolved? I no longer have Cadkey 19 (it’s 8 years old) on my computer but I think you can run the healing routine in 19. If not can you send me a file and I’ll see if it can be fixed in my KeyCreator 8 and returned to you as a SAT file. newmold@readytek.net