So I'm trying to make a background for a webtoon. But I want to render it with outlines and a cel-shaded look. So I looked up toon shader for blender and found one. But there are many objects. Do I have to add all the nodes for every object in the scene? Is there a way to just apply the same shader to every object? Also, what if the object has a plaid texture? The toon shader makes everything the same two colors.
I don't think you can to a "batch toon shader" conversion, or anything of the sort - your best bet is to copy (Ctrl+C) the "Toon Shadow" setup, and paste (Ctrl+V) it in your other materials individually, multiplying the shadows over whatever color (or texture) that is already there and bypassing the Shader (BSDF) to the output. Below is an example of toon shadows over a "plaid" pattern: