Merging meshes resulting in gaps

[Eric-R-Liang]

When I merge multiple triangulated meshes together, the resulting geometry has small gaps between its components. It seems like the gaps occur at the merging points.

How can I get rid of those gaps without distorting the triangulations? Thanks.

[github-actions]

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[Eric-R-Liang]

I am using the boolean addition filter to merge the individual meshes

[banesullivan]

Can you share these meshes for us to try?

[Eric-R-Liang]

Yep, there is a total of 8 meshes.
Meshes.zip

[akaszynski]

This will get you a little closer. I'm afraid that the meshes are really far apart and it won't be possible to merge them all without corrupting the mesh as increasing tolerance starts to cause the faces to collapse.

import pyvista as pv

block = pv.MultiBlock()
[block.append(pv.read('Component_%d.stl' % i)) for i in range(1, 9)]

combined = block.combine(True).extract_surface()
merged = combined.clean(tolerance=0.6)
merged.plot(show_edges=True, lighting=True, background='w')

[Eric-R-Liang]

Thanks a lot for the suggestion. Just as a side note, I have a mesh like this:
tunnel_mesh.obj.zip

I want to systematically split it into individual components (doesn't matter if the 'component' is composed of 1 or multiple segments of the initial geometry, like using a bounding box for example, and within each bounding box there can be multiple segments), and remove 1 or multiple of those components. And I want to essentially, remove 1 or more of those components from the initial geometry (via boolean subtract maybe). Is there a way to do that?

I've tried using the clip_box method but I can't figure out a way to use it to systematically break down the geometry and adjust the number of components that I want split into.

[akaszynski]

This might be a good example for pyvista/pyvista#797.

For the time being, I'd use several clip planes spaced at regular intervals along the XZ and YZ planes. Use mesh.bounds to determine your initial ranges and then generate several planes to clip your mesh.