# What is the difference between the normal input and the height input of a "bump" node?

For the height input, I know that you plug in a B&W texture.

For the normal input, do you plug in the purple-y color normal map? Or do we plug that map into the color input of the "normal map" node instead? If so, what's the function of the normal input of the "bump" node?

• I know that you can use it to plug a Normal Map, as you say, in order to mix a Bump and a Normal map, you can also plug another Bump Map, I don't know if it has another role... Commented Sep 4, 2021 at 15:45
• normal map is basically a bump map, but with more info and better result (short answer)
– Emir
Commented Sep 4, 2021 at 16:46

As the manual says, the Normal input is

Standard normal input.

If you don't connect a normal map to a bump map's Normal input, the default behavior is to use the same normal map that's produced by the Texture Coordinates node's Object output.

So the input has the same uses for a bump map as it does for any other node that has a Normal Input: it provides the bump map with a starting point normal map that the height map is used to modify.

Normal map, the blueish textures, that represent curvature of surface, should be plugged in material via Normal map node. You cannot use normal maps directly, because you should convert them from local (tangent space) to world space using Normal map node.

And you can add some surface curvature on top of existing curvature, using Bump node. And it should be added after normal map processing in Normal map node:

So, Normal plug used for normals, but converted from tangent space. You can apply as many Bump nodes as you want using this way:

And also there is a bunch of nodes having similar input, for example Bevel node which can be used to soften edges in Cycles:

• This is what I'm looking for, thank you Commented Sep 5, 2021 at 8:05