Bump map modifier (bumpmap)
Bump mapping  is a simple technique for cheaply adding surface detail to a rendering. This is
done by perturbing the shading coordinate frame based on a displacement height field provided as
a texture. This method can lend objects a highly realistic and detailed appearance (e.g. wrinkled or
covered by scratches and other imperfections) without requiring any changes to the input geometry.
The implementation in Mitsuba uses the common approach of ignoring the usually negligible
texture-space derivative of the basemesh surface normal. As side effect of this decision, it is invariant
to constant offsets in the height field texture—only variations in its luminance cause changes to the
Note that themagnitude of the height field variations influences the strength of the displacement. If
desired, the scale texture plugin can be used to magnify or reduce the effect of a bump map texture.
Parameter Type Description
- (Nested plugin) : texture
- The luminance of this texture specifies the amount of displacement. The implementation ignores any constant offset—only changes in the luminance matter.
- (Nested plugin) : bsdf
- A BSDF model that should be affected by the bump map