Masked Based Texturing

The overview of the function as a whole may seem a little overwhelming but it is actually very simple and easy once you understand the basics. The nodes are color based commented, Red for the inputs of the node, green for the outputs, and the blue is where all the magic happens.

Here we see the start for the entire function. In the Mask Separator comment block, there is a Vector 3 input node that is going into three mask nodes, each separating the texture that is plugged into the input node into the three color channels (RGB). As you can from the image above, the Red Diffuse Input is being multiplied by the red mask node from the masking texture. This will make the red diffuse texture only appear within the red section of the mask. This is further explained below

In the "Blend Primary Mask Color" section, the node is multiplying the, for example, the red texture with the red section of the texturing mask. The first two texture channels (Red and Green in this case) are going into a lerp node to blend the two channels together, the alpha for the lerp is the channel color for the "B" input. So in this case, Red is going into the "A" pin and Green is going into the "B" pin. Therefore, the alpha of the lerp node is the green channel of the mask. It is then going into another lerp node with the blue channel going into the "B" and the Alpha pins.

Thats pretty much it! You can repeat the multiplying and lerping section multiple times for each map you have, such as normal maps, specular, metallic, roughness values, etc...