'UGrid' object has no attribute 'compute_normals'

[RyanConway91]

Hello, I am trying to intersect a mesh loaded from a vtk (a 3D irregular rectilinear grid from a finite difference model, 'mf_grid' variable below) with a wedge mesh loaded from some other commercial software (EVS, variable 'ugrid' below). I got both loaded in and they display correctly.

However, when I run:

grid_int = mf_grid.boolean(operation ='intersect',mesh2 = ugrid)

I get the error:

'UGrid' object has no attribute 'compute_normals'

Can I convert my meshes to structured using vedo or is there some way I can get around this?

Thanks

[marcomusy]

Sorry for the late reply, I'm afraid vedo does not support data structures like rectilinear grids (maybe in the future...) I suggest to explore a similar library which is also based on vtk and it is largely compatible with vedo.
If you just need to do visualization you can still make a mesh from the vtk (as you've done already) and then intersect those meshes:

import vedo
rgrid = vedo.io.loadRectilinearGrid("file.vtk")
msh1 = vedo.geometry(rgrid)
msh1.print()
msh1.cut_with_mesh(msh2)
vedo.show(msh1, msh2, axes=1)

[RyanConway91]

Your responsiveness has been amazing, no worries!

Ugh so I got my meshes into pyvistas, but I get what seems like the same issue as I got in vedo (error in pyvistas is 'UnstructuredGrid' object has no attribute 'boolean_intersection')

Is there something fundamental about an unstructured grid that makes these types of operations impossible (I have a rectilinear mesh and wedge mesh)?

Is there a way to convert these meshes to 'structured'? I ran both of the meshes through triangulate (in vedo and pyvistas) but I still cant intersect. I tried running them through "tetgen" (https://github.com/pyvista/tetgen) as well, but got an error on that one...

Seems like this should be a fairly common task in 3D computing. Am I missing an obvious solution or thinking about this wrong?

[marcomusy]

If i rember correctly the method is called clip() to cut a grid to output an unstructured grid but you will need to check the pyvista docs.
The boolean operation is only working with polygonal meshes.
Cc @banesullivan

[banesullivan]

In PyVista, the boolean operations are only available on the PolyData type. You may need to run the extract_surface() filter in PyVista to get a PolyData from an UnstructuredGrid.

Sorry for my delay!! Hope this helps!