invert a 3d model of facial fetures to make a mask

[snapstar]

Hi everyone,

Looking for some help with a problem I can't seem to solve. I want to make a 3d printed mask that is 0.5cm deep. The appearance of the outside of the mask doesn't really matter. What is important is that the mask fits exactly to the facial features of the wearer and that it is uniformly 0.5cm deep. I'm only doing small sections of the face at the moment i.e. the nose and ear.
I have a cubify sense 3d scanner which has given me good 3d models in .stl format. I have autodesk inventor and cubify design CAD software to work with and I can get other software if necessary. I can convert my .stl files to .SAT, .DWG and .IGES files if necessary. I want the output to be in .stl format.

Does anyone know how I could invert my image and make it uniformly 0.5cm in depth so it would fit facial features perfectly?

[awerby]

You might try a Boolean subtraction. Make a 1 cm oversized version of the face, which I'm assuming is filled in solidly. Then insert the original face and subtract it. This won't produce an exactly even shell, but it's probably close enough for most purposes. If the software you've got won't do that, try using Cubify Sculpt.

Andrew Werby
www.computersculpture.com

[curious aardvark]

or openscad - should be easy enough to do.

[snapstar]

Hi guys,
Thanks for your help so far. Every time I try and oversize the model and subtract the original in Autodesk Inventor I get this error.
" Create Combine feature failed.
nose2.ipt: Errors occurred during update
Combine1: Could not build this Combine
The attempted operation had problems trimming and discarding faces. Try with different inputs. "
Cubify Sculpt cant do it either and neither can netfabb basic. I have a limited amount of time to get this project finished and Openscad seems pretty complicated to learn from scratch. Plus my computer can't even seem to import a file using openscad.

What I'd really like to do is use something like the shell tool in Autodesk Inventor but the 3d model I'm importing has like 1700 surfaces so that's not possible. And if I derive the model as a surface and try and shell it, there is an error because the model has no volume.

Any other ideas would be appreciated.

[awerby]

1700 surfaces? Where did you get this thing? If you scanned the original face with the Sense scanner, you should have got one STL mesh forming a solid, not all these little surfaces. Did you use some kind of mesh-to-NURBS command on your STL? Can you combine all these different surfaces into one, perhaps with a Drape command?

Andrew Werby
www.computersculpture.com