add versus mix in cycles


I’ve looked all over the place for this and haven’t found a succinct answer. What is the difference between the add shader and the mix shader in cycles? When is it better to use one versus the other?


mix shader will always limit the output = 1
add shader can be higher > 1 so it is not a realist render
but can be used it’s an option!

also mix is not equal to add !
try it you’ll see the differences!


The mix shader will do a mix between various shading behaviors, so a value of 0 means that only the first shader is visible and 1 means you only see the second.

The add shader isn’t designed to strictly follow energy conservation, but it has its own uses. For example, it can be used in a ceramic material to add a sort of glaze to the material without having much of an effect on the visibility of the diffuse color, mainly because it adds the shading behaviors on top of each other (providing you try to tweak the base colors to keep it energy conserving).

Currently, I have tweaked a glass material I’ve had for a while to use the add shader node for adding the glossy component nstead of mix shader (with additional color operations to keep energy conservation), and the result with the new refraction node in trunk is a glass shader that doesn’t have the usual dark spots that would be seen otherwise in areas where the glossy component is mixed in).

So again, it has its uses (especially for artistic elements), but things like physical accuracy in many other materials are easier to maintain with the mix shader.

any chance you could tell me where I could find an example of a ceramic material you mentioned? It might help me get a better sense of what it is doing.