Difficulties of Texture Painting in Blender
In my time on BlenderArtists and Blender's StackExchange, I've seen dozens of questions about texture painting not working as expected. It seems like one of the more difficult topics for beginners, and even experienced users can run into snags. Fortunately, most texture painting problems are fairly simple to resolve.
I made a video a while back showing some solutions to some common texture painting problems and I've decided to share that information in a written article as well.
1: Make Sure You're Painting on the Intended Object
You can select multiple objects at once in Blender. Depending on what you're doing, you can work with all of them or only one of them at a time. Texture painting only allows you to work on one object at a time, so if you have multiple objects selected, you might not be painting the one you think you are. Texture painting also removes the Selected and Active object outlines, making it very difficult to tell which object is the Active object (the one you can paint on.)
The solution here is pretty simple- generally speaking, you should only select one object at a time when texture painting. If you're in Texture Paint mode and nothing is happening, try switching back to Object Mode and see if you accidentally selected more than one object.
2: Right Image and Material
This might seem obvious, but it's important to check and make sure you're using the right image and material. It's very easy to be painting, make some changes in the Shader Nodes, and suddenly you can't paint anymore. This trick usually fixes that specific issue. There are three things you should check here:
- Right image
- Right material
- Right render engine- if you have a Cycles only material, you can't texture paint in Eevee, and vice-versa
3: Check Your UV Mapping
UV Mapping can trip you up in two ways- you need to have a UV map to texture paint, and you need to have a good UV map to texture paint well. If you don't have a UV map at all, you won't see anything happen when you try to texture paint. You can fix this by unwrapping the object in Edit Mode:
U > Smart UV Project
Better UV mapping is possible (and you should definitely do it!), but Smart UV Project is a good starting place.
One other important thing to note is that objects can have multiple UV maps, especially models imported from other sources. If you're painting and seeing an unexpected result, make sure you're painting on the UV map you think you are. You can check this here:
4: Check Your Normals
This solution could potentially fix a huge variety of problems, not just Texture Painting. It's also a solution that seems to work frequently- I've seen dozens of questions saying "Why can't I texture paint?", and this was the solution. Long story short: if you try just one thing from this tutorial, try this one.
You can't texture paint with inverted normals. The problem is that it can be difficult to tell if your normals are inverted, just at a glance. Luckily, there's an overlay that will show you:
What does this overlay tell you? If the faces are red, the normals are inverted. If they're blue, they're correctly facing outward. You can texture paint on blue faces, you can't paint on red faces.
It's super easy to fix inverted faces; you can flip them like this:
5: Pen or mouse?
This one only applies if you're using a drawing tablet or stylus. if you have a drawing tablet connected, you can't usually texture paint with the mouse. This isn't always true, and I think it's a bug, but it does happen. One thing that occasionally works to fix it is switching out of Texture Paint mode, disconnecting the tablet, and switching back in. Ultimately, I'd recommend either painting with your mouse or with a stylus, trying to do both often doesn't work.
For Windows users, another thing that can help is setting the Tablet API to Automatic- not Windows Ink.
6: Check your tool/settings
It's very easy to think you're using the Draw tool but actually have the Fill tool or the Soften tool selected. If you're not seeing any results, or results you don't want, press T to open up your Tools panel and make sure you have Draw selected. It's also important to check the Radius and Strength of the Draw Brush, as well as the Blend Mode. You can find these here in the header:
There you have it- six simple solutions that will solve 90% of texture painting problems. Hope it helps! :)