Here’s another quick test I did. Perhaps not many learnings here, but it was nice to see that it could be done as this is a different kind of application.
Grabbed some scan data from Thingiverse on a lower jaw/teeth and hollowed it out. 450K+ triangles.
The hollowing process I followed was:
- clean model and fix holes as much as possible.
- run a decimation (polygon reduction) process on a copy of the entire ‘outer’ mesh of the teeth - get something relatively small - in the thousands of triangles (many modelers have this functionality)
- extrude negatively along normals - and INVERT the inner mesh
- combine both meshes in the same view
- use mesh painting on the inner mesh to push/pull individual verts as needed for basic fix up (this is the nasty part)
- load the entire thing into preform as ONE STL and DO NOT ALLOW preform to fix the mesh (for some reason, sometimes, letting preform fix the mesh eliminates the inner mesh if it is not topologically connected to the outer mesh. Gotta research this more, but this is why I do #1 above. (you can use a free online service to do that at: https://netfabb.azurewebsites.net/ - you just need a microsoft login account, which is free)
Decimated poly version of the teeth at right (offset for viewing)
Inner mesh in yellow wireframe. 600K outer mesh in black behind it.
Note that I did not punch any holes from the inner to the outer mesh. That proved to be a problem as I did have one blow out that you will see on one of the teeth on the right side of the mouth (from the mouth’s perspective).
I used automatic support generation on this one
Cleaned up pretty easily.
See the blow out on the right side here in the middle of the tooth. I may have made the inner wall to thin in this area. BUt I also forgot to punch a hole!
pretty good detail (this is 0.05)
Just realized the poor guy/girl had no molars on the right side. Ouch.