Need software recommendation

[Toffer]

Hi. I am trying to figure out the best way to add geometry to the inside of scans. I don't want to reverse-engineer the outer surfaces because I need to keep them. But I want to add holes, passageways, shell the surface in a CAD type application. The use is for creating antique car parts, like an old carburetor. The surface uniqueness must remain, but the internals must be accurate. Since the scans are only able to get the edge of the holes, I need to add the CAD elements to finish the job. I know a CMM with Polyworks or similar would be the ideal setup, but $$$. I can purchase Spaceclaim and use their STL prep for AM module, but that's $$. I was hoping to find something more like $ or free.

Anybody know of anything?

Thanks!
Toffer

[fred_dot_u]

You may discover that Blender can be of use to you. http://www.blender.org/
The price is right, free, and there are uncounted resources to learn the program. The latest version is 2.72, but the more common usage is aimed at 2.69, the version I'm struggling to learn. The struggling part is not the program, it's the alleged mind getting stuffed with so many short cut keys, so many concepts, so much flexibility.

Each time I begin to learn a new lesson from the tutorials, I have to relearn the previous stuff, as the synapses fail me too quickly, but the program is quite easy to understand via the tutorials. I am constantly amazed at the flexibility and at the capacities of the software, especially considering the price.

I have used Blender in concert with Meshmixer http://meshmixer.com/, also free, to perform simple actions on .STL files.