How to use switches?

[banesullivan]

I can't complete the following example which is a hacked attempt to reproduce the example at the bottom of this page: http://wias-berlin.de/software/tetgen/features.html

from pyvista import examples
import tetgen

cow_mesh = examples.download_cow().tri_filter()

cpos = [(13., 7.6, -13.85),
 (0.44, -0.4, -0.37),
 (-0.28, 0.9, 0.3)]

cow_mesh.plot(cpos=cpos)

tet = tetgen.TetGen(cow_mesh)
tet.tetrahedralize(switches='-d')

Last line above throws error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-44-ff4a5030d854> in <module>
----> 1 tet.tetrahedralize(switches='-d')

~/Documents/OpenGeoVis/Software/tetgen/tetgen/pytetgen.py in tetrahedralize(self, switches, plc, psc, refine, quality, nobisect, coarsen, metric, weighted, brio_hilbert, incrflip, flipinsert, varvolume, fixedvolume, noexact, nostaticfilter, insertaddpoints, regionattrib, cdtrefine, diagnose, convex, zeroindex, facesout, edgesout, neighout, voroout, meditview, vtkview, nobound, nonodewritten, noelewritten, nofacewritten, noiterationnum, nomergefacet, nomergevertex, nojettison, docheck, quiet, verbose, vertexperblock, tetrahedraperblock, shellfaceperblock, nobisect_nomerge, supsteiner_level, addsteiner_algo, coarsen_param, weighted_param, fliplinklevel, flipstarsize, fliplinklevelinc, reflevel, optscheme, optlevel, delmaxfliplevel, order, reversetetori, steinerleft, no_sort, hilbert_order, hilbert_limit, brio_threshold, brio_ratio, facet_separate_ang_tol, facet_overlap_ang_tol, facet_small_ang_tol, maxvolume, minratio, mindihedral, optmaxdihedral, optminsmtdihed, optminslidihed, epsilon, coarsen_percent)
    498                                                           optminslidihed,
    499                                                           epsilon,
--> 500                                                           coarsen_percent)
    501         except RuntimeError:
    502             raise Exception('Failed to tetrahedralize.\n' +

~/Documents/OpenGeoVis/Software/tetgen/tetgen/cython/tetgen/_tetgen.pyx in tetgen._tetgen.Tetrahedralize()

TypeError: a bytes-like object is required, not 'str'

[akaszynski]

It's the code's fault. It's not a frequently used module for us, so code coverage isn't a huge issue, but I'll clean it up a bit.

The good news is this is a great demo for pyvista. The bad news is I need to make a wheel for pymeshfix and push a patch for tetgen as there was a bug due to a refactoring.

I'll comment back when the modules are updated.

import numpy as np
import pyvista as pv
from pyvista import examples
import tetgen
import pymeshfix

cow_mesh = examples.download_cow().tri_filter()

cpos = [(13., 7.6, -13.85),
 (0.44, -0.4, -0.37),
 (-0.28, 0.9, 0.3)]

# cow_mesh.plot(cpos=cpos)

tet = tetgen.TetGen(cow_mesh)
tet.make_manifold()
tet.tetrahedralize()

cow_grid = tet.grid

# plot half the cow
mask = np.logical_or(cow_grid.points[:, 0] < 0, cow_grid.points[:, 0] > 4)
half_cow = cow_grid.extract_selection_points(mask)

plotter = pv.Plotter()
plotter.add_mesh(half_cow, color='w', show_edges=True)
plotter.add_mesh(cow_grid, color='r', style='wireframe', opacity=0.2)
plotter.camera_position = cpos
plotter.show()

# construct silly spinning cow
plotter = pv.Plotter(off_screen=True, window_size=[400, 400])
plotter.open_gif('/tmp/tmp.gif')
plotter.add_mesh(half_cow, color='w', show_edges=True)
plotter.add_mesh(cow_grid, color='r', style='wireframe', opacity=0.2)
plotter.camera_position = cpos
plotter.write_frame()
nframe = 36
deg = 360./(nframe + 1)
for i in range(nframe):
    half_cow.rotate_y(deg)
    cow_grid.rotate_y(deg)
    plotter.update()
    plotter.write_frame()
plotter.close()

[banesullivan]

Woah awesome! Thanks, @akaszynski!

The good news is this is a great demo for pyvista

Oh yeah! This is an excellent demo for PyVista - which is why I started playing around with this toolset

[banesullivan]

I'll include this in #6

I'll comment back when the modules are updated.

Let me know when you patch things up and then I'll make sure PR #6 is good to go!

[akaszynski]

Use the latest modules and you'll be good to go.