Decimation

Decimate a mesh

# sphinx_gallery_thumbnail_number = 4
import pyvista as pv
from pyvista import examples

mesh = examples.download_face()

# Define a camera potion the shows this mesh properly
cpos = [(0.4, -0.07, -0.31), (0.05, -0.13, -0.06), (-0.1, 1, 0.08)]
dargs = dict(show_edges=True, color=True)

# Preview the mesh
mesh.plot(cpos=cpos, **dargs)

Out:

[(0.4, -0.07, -0.31),
 (0.05, -0.13, -0.06),
 (-0.09918995010726926, 0.9918995010726926, 0.07935196008581541)]

Now let’s define a target reduction and compare the pyvista.PolyData.decimate() and pyvista.PolyData.decimate_pro() filters.

target_reduction = 0.7
print(f"Reducing {target_reduction * 100.0} percent out of the original mesh")

Out:

Reducing 70.0 percent out of the original mesh

decimated = mesh.decimate(target_reduction)

decimated.plot(cpos=cpos, **dargs)

Out:

[(0.4, -0.07, -0.31),
 (0.05, -0.13, -0.06),
 (-0.09918995010726926, 0.9918995010726926, 0.07935196008581541)]

pro_decimated = mesh.decimate_pro(target_reduction, preserve_topology=True)

pro_decimated.plot(cpos=cpos, **dargs)

Out:

[(0.4, -0.07, -0.31),
 (0.05, -0.13, -0.06),
 (-0.09918995010726926, 0.9918995010726926, 0.07935196008581541)]

Side by side comparison:

p = pv.Plotter(shape=(1, 3))
p.add_mesh(mesh, **dargs)
p.add_text("Input mesh", font_size=24)
p.camera_position = cpos
p.reset_camera()
p.subplot(0, 1)
p.add_mesh(decimated, **dargs)
p.add_text("Decimated mesh", font_size=24)
p.camera_position = cpos
p.reset_camera()
p.subplot(0, 2)
p.add_mesh(pro_decimated, **dargs)
p.add_text("Pro Decimated mesh", font_size=24)
p.camera_position = cpos
p.reset_camera()
p.link_views()
p.show()

Out:

[(0.8136259721113195, 0.0024271619131386035, -0.6008839297564575),
 (0.052799999713897705, -0.1280001476407051, -0.05743680661544204),
 (-0.09918995010726926, 0.9918995010726926, 0.07935196008581541)]