clip_box behavior is broken

Hi,

to follow up on the thread started in Discussions, clip_box behavior is broken, as the clipped part doesn’t match the passed box.

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To Reproduce

import pyvista as pv
from pyvista import examples

mesh = examples.load_airplane()

# Use `pv.Box()` or `pv.Cube()` to create a region of interest
roi = pv.Cube(center=(0.9e3, 0.2e3, mesh.center[2]),
              x_length=500, y_length=500, z_length=500)

extracted = mesh.clip_box(roi, invert=False)

p = pv.Plotter(shape=(1,2))
p.add_mesh(roi, opacity=0.75, color="red")
p.add_mesh(mesh)
p.subplot(0,1)
p.add_mesh(extracted)
p.add_mesh(roi, opacity=0.75, color="red")
p.link_views()
p.view_isometric()
p.show()

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Screenshots

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System Information:

  Python 3.8.10 (default, Nov 26 2021, 20:14:08)  [GCC 9.3.0]

           pyvista : 0.33.2
               vtk : 9.0.1
             numpy : 1.21.0
           imageio : 2.14.1
           appdirs : 1.4.4
            scooby : 0.5.11
        matplotlib : 3.4.2
             PyQt5 : 5.12.3
           IPython : 7.22.0
              tqdm : 4.48.2

According to @banesullivan , the regresion occured in v.0.33.0

Also, from my investigations, in the previous example if instead of the Cube object, we pass its bounds, then clipping is sane. However if the cube is rotated, then the clipping breaks (albeit in a different way).

Edit: to complete, the bug is not linked to the invert parameter either

[eino]

Well seen! Indeed it does fix the problem 👍

I can prepare a PR to fix it.

[eino]

Hi, I ran a git bisect, and found the regression occurred in commit 4b83f5c9

And more precisely, it’s the change to utilities/geometric_objects.py, setting the parameter clean=True that made Cube not suitable to be passed to clib_box. If we change the above example to pass clean=False to the Cube creation, then the clipping works as expected.

I wonder if the Cube should be cleaned by default. If it does, maybe a warning should be placed in clip_box doc, and examples amended. What do you think?