I am not on Alibre, but I import from SolidWorks.
I find the igs easier to work with in VM because it gives you seperate surfaces instead of 1 big lump (think extract edge curve function here or ability to create regions).
When saving stl in the CAD you need to set the triangle resolution to very fine.
Machining preferences in VM need the part sampling to be set to fine (BEFORE YOU OPEN THE IMPORTED PART).
The higher the quality of 3D you work with in VM will dictate how slow your computer works. I haven't recorded a bench mark but long ago I tried the same part at course setting and at fine setting and 3D mop generation went from 5min. to 45min.
You also need to chose the correct options for "output as linear segments". There are also options for arc fitting.
Dave - what machining strategies are u referring to? it makes a difference.
If you are doing 2.5d either chain or join your regions (or draw new ones).
Hopefully this will get you going better.
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