# triangulate concave point cloud

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Hi all,

I have a concave shape represented as a point cloud. Any idea how can I skin it in houdini? traingulate2D doesn't work very well.

Thanks for help.

kuba

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Hi all,

I have a concave shape represented as a point cloud. Any idea how can I skin it in houdini? traingulate2D doesn't work very well.

Thanks for help.

kuba

no sure about in Houdini, but I ran over this the other day:

http://meshlab.sourceforge.net/

Haven't tested it yet, though.

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Yes I think that's the only alternative which works for me right now. The thing is I have to do lot of tests and going back and forth between two applications is very painfull .

Piping things using unix command would be nice workaround, but I don't think meshlab can be run from command line.

Anyway, thanks for feedback

kuba

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I have a concave shape represented as a point cloud. Any idea how can I skin it in houdini? traingulate2D doesn't work very well.

Well, triangulate2D clearly doesn't work since it's called 2D and you have a 3D problem.

Does your generated surface have to go through the original points? If not, then one can reconstruct the surface via use of the BlendPose CHOP to determine the best density, which the IsoOffset SOP can then regenerate a surface from. I've attached a file I was playing from awhile back that does this. A big caveat with this approach though is that it requires normals on the points. Normal estimation for point clouds is outside the scope of this example.

blendpose_iso.hip

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• 5 months later...

You CAN use the triangulate2D.

1 ) pipe your points into a POINT SOP and set \$TZ to 0

2 ) your points are now on a 2D plane, so you can use the triangulate2D SOP

3 ) pipe the result into another POINT SOP ( input 1 )

4 ) pipe your original points into the second input of the POINT SOP ( input 2 )

5 ) replace \$TZ with \$TZ2 ( that put the TZ data back )

6 ) job done.

Hope that helps,

Julien

Well, triangulate2D clearly doesn't work since it's called 2D and you have a 3D problem.

Does your generated surface have to go through the original points? If not, then one can reconstruct the surface via use of the BlendPose CHOP to determine the best density, which the IsoOffset SOP can then regenerate a surface from. I've attached a file I was playing from awhile back that does this. A big caveat with this approach though is that it requires normals on the points. Normal estimation for point clouds is outside the scope of this example.

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Jason, did you have any success with cgal-python in the end?

Edited by kubabuk
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Eureka!!! :notworthy:

Jason, did you have any success with cgal-python in the end?

Only kinda, with Ubuntu. They have a package you can install with the Package Manager which makes things easier. I never managed to compile CGAL for Python on any other platform successfully, meaning that the general public would never bother trying. I'd rather work on a project that has the hope of being useful to other people than just me.

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