Tet Mesh Internal Surfaces

[ebird7]

Hello,

This program is wonderful. However, for my application, I need to generate a tetrahedral mesh of overlapping bodies while preserving internal surfaces. Using geogram intersect/vorpalite or graphite, I cannot figure out if its possible to preserve the internal surfaces in the tetrahedral mesh. While I can turn off "remove_internal_shells" in the intersection boolean op, it seems to only preserve the outer hull (like a union) when the tet is generated.

While I'm at it, I would also like to apply a material attribute to each volumetric region corresponding to the original bodies. Is this also possible while preserving the internal surfaces? Thanks so much.

[BrunoLevy]

Hello, can you show us an image (or even better share some input data, you can attach files here), I will take a look.
Best,
--Bruno

[ebird7]

Hi Dr. Levy, thanks for the reply. I attached an input mesh "fragmentationEx_0.off" (change .txt extension to .off bc github won't let me upload). Its a simple example mesh of some overlapping prisms. You can see in the initial mesh there are some overlapping bodies:

Then when I perform tet meshing, the internal surfaces are not constrained in the volumetric elements. When I do a cross-section I want to see a clearly defined surface partition at those intersection lines, but instead its homogenous.

Ideally I would want each of the "Weiler" volumes to have different colors with the clearly defined tetrahedral partitions along the internal surfaces. Is there a way to accomplish this? Thank you.

fragmentationEx_0.txt

[BrunoLevy]

I'd try meshing the 5 parts independently, then merge the different parts.
Let's call A,B,C,D the four cubes from left to right,
This means you need to create then tet mesh:

• $A - B$
• $A \cap B$
• $B - A$
• $C$
• $D$