Cycles - negative values
Up until fairly recently - Cycles would allow negative values to be fed into shaders as RGB values or negative emission values to be set for the emission shader (resulting in the emission sucking light out of the scene rather than pumping it in).
Whilst fairly niche in it's use case, I did used this capability to great effect in order to create several interesting shaders and effects (in effect, it allowed shader subtraction).
However - in recent builds, this capability appears to have been removed and any negative RGB values or negative emission values fed into a shader are now simply clamped at zero.
Does anyone know if there is there a reason for this change?
2 Comments
It has not been removed. You just need to set the Emission Sampling in the Material Settings to None.
Thanks - that works for emission materials, but the negative RGB values still don't work as they did before (e.g. the node setup shown above).