How to separate one material into multiple materials (e.g. one material for shirt, one for pants, etc)?

Question

I downloaded a model that only has one material. Is it possible to separate it into multiple materials (e.g. one material for shirt, one for pants, etc)?

I would be using this model in Unity and would like the ability to change for example the pupil color within Unity without affecting the color of everything else. Only way to do that is have separate materials for each part but I'm too new at Blender to know how yet.

Thanks for any help.

Answer 1

If I understand well, you just need to make a copy of the material for parts of your object so that each part can have its own material and can be changed without affecting the others, right?

Here I have a sphere with a green material applied to it :

To add a new material slot, you just click the + button on the right :

The new material slot is empty, you can either add a completely new material with + New or you can chose from the already existing one with the dropdown list (this is what you want if I understood you well) :

You have now two material slots but right now they are currently using the same material and if you try to change one of them, the other one will change :

It's because the two material slots are using the same material data-block and you can see here how many other slots are sharing that same material data-block (Blender refers to them as users and the little number that you see near the name is the number of users for the material) :

Here we have 3 users. To make the current user have its own copy of the data-block, you can just click on that number :

After doing that, you now have two different materials and you can now edit either of the two without affecting the other one :

Here, I renamed the two materials and changed the color of the second one. (Notice also that the red material doesn't have the little number near its name anymore since it has now one user)

Now you can just go to edit mode and select any part of the mesh that you want :

And then, select the material you want to apply to it and click Assign :

You can repeat this steps for as many parts of the object as you want.

Answer 2

If you insist on keeping it all into one material:

1- make a new material

2- in the shading tab of that material, build your two shaders

3- join the two shaders with mix shaders node.

4- in the factor input, use a image texture

5- paint your image texture with black and white(or values between)

(There's a problem with the image below, the UV output of Texture Coordinate should be connected to Mapping node. sorry! )