Edit mode required first for Texture Paint to work When I have multiple textures to paint on then I need to go to edit mode first before I can paint on them.
Here I show what is going on:
https://www.youtube.com/watch?v=biUbiMUzCHE
Why is the first going to edit mode required? It is really confusing, especially for new users cause there is nothing indicating why texture paint is not working when you not went to edit mode.
I hope someone can explain.
Try mixing the colors in the shader editor first, then from the 3D Viewport switch to Texture Paint mode (Ctrl+Tab, 9).
In Texture Paint mode from the Properties Panel (N), select the Tool tab.
Select the base material, then you can select which texture you would like to paint on from here.