What is Anisotropy?

A real world example of Radial Anisotropy. Photo by Kurtis Garbutt

Anisotropy is similar to a glossy shader, only it pulls the reflection in a certain direction:

Comparison of a glossy shader and a (linear) Anisotropic Shader

Take this example:

Viewed from the side, the reflection is stretched sideways.

But when viewed 90 degrees to the right, it creates a very different reflection:

So Anisotropy allows us to (finally) create materials like; brushed metal, CDs, vinyl, fry pan bases,

kitchen sinks etc.

Brushed metal. A real world example of Linear Anisotropy. Photo by Guido Muermann

Using the Anisotropy Shader

For this example we will be applying both linear and radial Anisotropic shading to a saucepan. Modelling

the saucepan isn’t really part of the core lesson of this tutorial, so I won’t write it out, however it’s

covered in the video version at the top of the page.

With the saucepan selected add a new material, and from the shader dropdown, select Anisotropic

BSDF.

Go to the node editor and you should see the Anisotropic Node. Here’s a brief description of what each

setting does:

Set the Roughness to 0.05 and the Anisotropy to 0.95.

The saucepan should now look like this:

Pretty easy right? Well the base is finished, but technically the walls aren’t correct yet as it’s using the

default radial anisotropy when it should be using linear.

Creating Linear Anisotropy

So we need to make another material and only assign it to the walls.

Linear shading needs UV coordinates to know which direction the light should stretch. So before we can

continue, we need to UV unwrap the saucepan.

In front view select all the vertices, press U and select Cylinder Projection.

Then select the base of the saucepan and from top view, press U and select Project from View

(Bounds).

If you look at the UV view you should now see this:

The anisotropy will stretch the light vertically along the UV coordinates. So if you’re using this tutorial for

another purpose, make sure to rotate the uv coordinates according to which way you want the light to

stretch.

Now that you’ve UV unwrapped it, go back to the Node Editor (making sure the Linear material is

selected) and add a Tangent node (Input>Tangent). Set the type to UV Map and select the name from

the drop down box:

Throw it in a scene and you’re finished!

I hope you enjoyed this tutorial! If you create something cool, post it in the comments below