1) Load a surface
Note: If you try with another surface that has holes, or that is non-manifold, see this tutorial.
As with most scanned meshes, the quality of the triangles makes it difficult to use it for tetrahedral meshing.
2) Remesh the surface
Mesh->remesh->remesh target edge length: -100 (or use -200 for smaller triangles)
This generates nearly equilateral triangles.
3) Create a tetrahedral volume
Scene->create object type: WhetGrid (this stands for "weakly heterogeneous grid") name: armadillo_tet Select armadillo_tet in object list
4) Tetrahedralize with bundeld TETGEN
Geometry->stuff surface surface name: armadillo quality: 2.0 (use 1.5 for smaller tets)
5) Visualize the result
In viewer controls (top left) selected only In shader pane (right) border->off solid slices->on x_slice->on
6) A more complicated example
Let us try it:
Scene->create object type: WhetGrid name: dragon_tet Select dragon_tet in object list Geometry->stuff surface
This fails. This is due to the fact that the surface has self-intersection. Fortunately, TETGEN detects them, and Graphite marks them as red dots (locks). They are under the mouth of the dragon
Now that we understand the problem, let us fix it (using Laplacian smoothing):
Mesh->lock/unlock->grow locks nb_iter: 7 Mesh->lock/unlock->invert locks Mesh->optimizer->optimize geometry
The surface no longer has self-intersections and can now be tetrahedralized.
Select dragon_tet in object list Geometry->stuff surface Shader pane border: off solid slices: on x slice: on