Diffuse Color

The diffuse color sets how bright the surface is when lit directly with a white light source (intensity at 100%). It defines which percentage for each component of the RGB spectrum which does not get absorbed when light scatters beneath the surface. Metal's normally have a black or very dark diffuse color, however, rusty metal's need some diffuse color. A diffuse map is usually required.


The diffuse weight.

Diffuse 0-1

Direct Diffuse

The amount of diffuse light received from direct sources only. 

Indirect Diffuse

The amount of diffuse light received from indirect sources only. 


The diffuse component follows an Oren-Nayar reflection model with surface roughness. A value of 0.0 is comparable to a Lambert reflection. Higher values will result in a rougher surface look more suitable for materials like concrete, plaster or sand.

Roughness 0-1


Backlight provides the effect of a translucent object being lit from behind (the shading point is 'lit' by the specified fraction of the light hitting the reverse of the object at that point). It is recommended that this only be used with thin objects (single sided geometry) as objects with thickness may render incorrectly.  

In certain situations backlighting may work fine with thickness (ensure that the diffuse ray depth level is above 1).

Bounce Factor

The relative energy loss (or gain) at each bounce. This should be left at its default value of 1.0, which is the only value with meaningful physical sense. Values bigger than 1.0 will make it impossible for GI algorithms to converge to a stable solution, and values smaller than 1.0 will have a reduction in the color bleeding effect.


Bounce Factor gives more control over GI bounces on a per shader basis rather than on a global basis via the render settings. In the following example the Bounce Factor has been changed for the shader assigned to the red sphere. When the Bounce Factor of the red sphere has been set to zero, the GI rays traced from the white floor to the sphere will not see it and therefore will not receive any color bleeding.

Specify whether Fresnel affects the diffuse component.



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