PBR materials¶

PyVista's pbr=True enables the metallic / roughness path on the Principled BSDF in Blender. The bridge maps metallic and roughness straight onto the matching BSDF inputs; Cycles then gives true Fresnel reflection and view-dependent shading that the VTK Phong shader can't reproduce.

import pyvista as pv

bunny = pv.examples.download_bunny()

plotter = pv.Plotter(off_screen=True, window_size=[1280, 960])
plotter.add_mesh(
    bunny,
    color="#dec27c",
    pbr=True,
    metallic=0.3,
    roughness=0.35,
)
plotter.set_background("#1a1d22")
plotter.camera_position = [(0.2, 0.18, 0.25), (-0.02, 0.1, 0.0), (0, 1, 0)]

plotter.blender.render("bunny_blender.png", samples=64)
plotter.close()

Full script: examples/pbr/bunny_pbr.py.

How the mapping works¶

Phong → PBR (when pbr=False)¶

When pbr=False the bridge still goes through the Principled BSDF but converts the Phong specular exponent using the Walter et al. roughness fit r = sqrt(2 / (n + 2)) from prop.specular_power, with prop.specular driving the BSDF specular weight. Glossy plastic look without setting pbr=True.

Unlit (when lighting=False)¶

Setting lighting=False on the actor swaps the Principled BSDF for an Emission shader so the surface ignores scene lights — matches VTK's flat path. Useful for label meshes, overlays, or stylised renders.