Material Based on Distance from Origin

Question

I am trying to make a brain coral.

Currently I'm using a displacement modifier with an actual brain texture, which looks quite good. However, I cannot figure out how to get the material to work right. My coral is based off of this image:

I want to make a gradient material that makes the deeper groves orange, and the extruded parts bright yellow, based on the distance from the center of the mesh. All of the online methods that I've tried so far have resulted in a gradient from one side of the mesh to the other.

Is there any way to do what I'm attempting?

I am currently using Blender 2.8 with EEVEE.

Answer 1

Considering your mesh vertices are approximately centered around the object origin (if not, this will not work as expected with this solution), you can use this kind of setting:

From the object output of texture coordinate (which gives x,y,z values relative to the origin).

Calculate the distance to the center (dot product then square root).

Subtract some value which may correspond to the inner orange part distance to the origin.

Input this result into a colorramp tuned to mix yellow/orange appropriately.

Answer 2

Lemon's answer works well and is what I was trying to achieve, but another simple answer has also occurred to me for my particular situation. Since I'm using a displacement texture to control the shape of my object, I can simply use that texture as a factor for the color ramp. I might still use the texture coordinate based method though as it will allow me add detail to the mesh without a displacement map.