The teapot and the dragon, four ways

Ray tracing loading…
off from ray tracing–
Radiation model
Fig. 7 — The Utah teapot and the Stanford dragon in a small room with a red and a green wall, lit by one small lamp. Pick a radiation model and drag the divider to compare it with ray tracing. All images were rendered for this post with a physically based path tracer (Mitsuba 3, 16,384 rays per pixel). Ray tracing is the reference; the other three show each model's typical error on this scene rather than the output of an engineering solver: no exchange keeps only light that comes straight from the source; spherical harmonics (P₁) delivers the source's light as a smooth glow and cannot hold a sharp shadow; discrete ordinates (DOM) lets the light leave the source only along the 24 directions of an S₄ set. The “off” meter is the average difference in brightness from the ray-traced image.