Cutting 3D surfaces

[Wendy María Arango]

Hi there! I hope you’re doing fine.

It happens I’m trying to understand how 3D meshes work. So far, I’ve understood how GMSH files work and I’ve been trying to understand how MeshLoader and TetrahedronSetTopologyModifier work. But it’s complicated since it has a lot of stuff and documentation does not help a lot regarding this topic.

I’d like to know how that Modifier works, which should be the process to cut a 3D surface? I mean, adding triangles, then edges, then points? How can we modify data structure?

If I could get a small answer about this, I’d be grateful.

Thanks y’all!

[Hugo]

Hi Wendy

I will discuss this in the coming days with the “topology” guys, and get back to you.
Best,

Hugo

[epernod]

Did someone say topology? Did I saw the bat-topology-signal?

Hello Wendy,

yes sorry, all those components are still a bit messy. It is on the todo list to have a clearer api.

Until then, for basic suppression/add of topological elements, I would suggest to have a look at those scenes:
https://github.com/sofa-framework/sofa/tree/master/examples/Components/topology/TopologicalModifiers

they use a component called
<TopologicalChangeProcessor listening="1" filename="RemovingTetra2TriangleProcess.txt" />

which is used to script the topological operation (mainly for tests).
This will give you a good starting point in the code on how to use the modifiers.

Do not hesitate if you need more help.

best regards,

[epernod]

And be sure to work on a nearly up to date version of SOFA from github because several bugs on the topology operation have been fixed in the past months.

[Author]

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