I have a principled bsdf. Under roughness, I have maps that I would like to connect to it. As I'm adding a normal map to my roughness map, I'm thinking of putting the map through a diffuse bsdf. Is it possible to connect the diffuse bsdf to the principled bsdf under roughness? I can't figure out how as the node lines turn red which I guess means it's invalid.


1 Answer 1


No you can't connect a shader's output to a the input of another shader. Different kind inputs should not be mixed. Green goes with green, purple with purple, Yellow and Grey can be mixed if you know what you are doing.

Refer to these links to understand what each color socket is for:

What is the meaning of the color of the node sockets in the node editor?


Cycles - (Shader) Nodes - inputs outputs - What are the exact data types?

Normal maps and roughness maps are different kind of information and each of them can be connected to their corresponding input.

Normal map would go to the normal input socket.

Roughness to roughness input on the same principled BDSF node.

  • $\begingroup$ thank you for your reply! i understand now that this is not the way to do it. $\endgroup$
    – shavonne
    May 30, 2020 at 8:23
  • $\begingroup$ @shavonne If the answer heped, please mark it as accepted so it can help others :). $\endgroup$ May 30, 2020 at 18:22

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