# How can i modify a Displacement texture roughness?

If i add a single texture as a Displacement texture on Cycles, how can i modify? i had been trying with Mix but i don't get the right number, or maybe is the wrong option?

• Did you try a math node set to multiply? – VRM Jun 9 '15 at 14:53
• what do you want to modify about the texture? – David Jun 9 '15 at 15:12
• Hmm, when i added the math node now the object doesn't show up in the render. I want to for example add the same image texture as a bump, but making the 'markings' based on the same image not too sharp/rough, like using a 30% of the image – beavoru Jun 9 '15 at 15:17
• Using a ColorRamp node ? (and maybe with Math also) – Mr Zak Jun 9 '15 at 15:22

Displacement expects a number, not a color. You can see that because the displacement's input is grey whereas a color-value is marked as yellow in the Node Tree.

So you normally convert the color to a value via a RBG to BW Node. You then can use Math nodes to freely manipulate the value until it fits your needs. In your case I would use a Multiply and then play with the factor a bit until satisfied.

I've used a Voronoi Texture as a stand-in for whatever texture you want to use, so you can just swap that out.

Note: I've heard that this conversion is done automatically when you connect a color-output to an value-input. Apparently this won't lead to any problems, so you can leave out the RGB to BW node and just connect the color output to the Math input (thanks @TARDIS Maker).

• I've never had problems where the RGB to BW node is actually required. It usually does the conversion perfectly fine without it. Another example where this works, is with the conversion of an RGB to a Vector. They're both a 3 Vector, so they can do a conversion with out any issues. – TARDIS Maker Jun 9 '15 at 19:30

You can use the same image texture as a color and bump maps at the same time. I'll show you how it works using the image below.

Set up the nodes as pictured below. Add a RGB to B&W node (Add-->Converter-->RGB to B&W). It will turn your color texture to a B&W so you may use it for bumps. To control the bumpiness size just add a Mix RGB node, set its type to Multiply and the color to white (if you're using a lower socket) or black (if you're using a upper socket). Change the Factor to control the bump size.

Here's the result:

Instead of adding the Mix RGB node you may add a Math node (Add-->Converter-->Math). Set its type to Multiply as well and play with the Value slider.

Result:

There is also the other way. Add a Bump node (Add-->Vector-->Bump) and set it up as pictured below. Increase the Strenght to make the bumpiness bigger.