Numpy array to surface reconstruction

#1

Hello.
I have a point cloud from a numpy array and I’m trying to get the surface but all methods give me errors.
Here’s a look at the point cloud:

image
image768×540 103 KB

Alpha Shapes:

RuntimeError: [Open3D ERROR] [CreateFromPointCloudAlphaShape] invalid tetra in TetraMesh

BPA:

[Open3D WARNING] [SimpleShaderForTriangleMesh] Binding failed with empty triangle mesh.
[Open3D WARNING] [SimpleShaderForTriangleMesh] Binding failed when preparing data.
[Open3D WARNING] [SimpleShaderForTriangleMesh] Something is wrong in compiling or binding.

Poisson Surface Reconstruction gives me:

image
image701×649 17 KB

Is there something I’m missing beyond assigning the points and computing normals?

#2

Is the Poisson surface OK? If it is, then obviously something is wrong with the parameters you are using in Alpha blend. The example in documentation is quite good. Have you tried varying the parameters in line with it?

1 Like
#3

Thanks for the reply :slight_smile:

Alpha Shapes:
I’m not so sure the problem is simply parameters. There are several github issues about the same alpha shapes error namely:


A proposed workaround lets me see the point cloud plus the mesh but not invoke alpha shapes:
image
image1119×895 310 KB

BPA:
It does indeed seem to be parameters. The warnings end above a certain threshold though I’ve been unable to find appropriate radii but that’s beyond the scope of this issue.

PSR:
Yes it is correct.

Turns out the tutorial parameters are too small for this case and the increments themselves were too.
Thanks again for the quick reply.