I had a somewhat similar issue not too long ago. In my case it had to do with machining a mold from a (cartoon) face within a predefined block of material (and all the usual pins, gate, etc. features). So the only way was to import an organic shape into a geometric/mechanical environment… not pretty.
BUT, over on the GrabCAD site (question does not seem to be available anymore), I asked a very similar question and got the following responses:
- use NETFABB (or Geomagic Design X)
- into 3dStudio, then SAT, then Inventor, then STEP…
- use InStep Studio 3D
I tried out the different tools and the Geomagic tool is by far the most advanced (read: complicated) but also most expensive (I saw $20k !!!). Netfabb is very good, but expensive ($4.6k/yr as of this writing - don’t get me started on these annual-only license packages). The Inventor route wasn’t an option (again, cost). The last one is the one I ended up using.
InStep Studio (used to be just InStep, the InStep Studio, now InStep Studio 3d… go figure) is low cost (I got a 30% off discount shortly after signing up for the 10-day trial, you might be able to just ask for a discount) at $175 (that is for a permanent license!) and does a number of things (have yet to figure out some of them) but one thing that worked well for me was the conversion to a smooth (NURB?) surface body that is far more efficient than using the full triangle collection (and works better in my CAD application too when it comes to cuts/bools). I did need to go through the tutorials to figure out some of the detail settings, but that tool all of about 10min… You can probabably google it, but this is the (new) direct link (today, anyway): https://instepstudio3d.com
If you can post the model you are using/trying to use, I would be happy to take a quick look and let you know what I can see/do…