How can I use the baked normal map (the purplish map) into the Texture Paint mode?

Question

I would like to add some bump features into the existing normal map just like what you did in the Painting Bump map video. The existing normal map was created by using baking method to get the beveling effect on the hard edges which having the purplish color. Now, I would like to add more bump features into this map, but I'm not sure how to convert the purplish color into gray-scale (black and white) as demonstrated in this video?

Answer 1 · 2019-02-28T21:19:13Z

Kent Trammell replied February 28, 2019 9:19pm

I don't think you can paint the purplish normal map in Tex Paint mode. At least not in the way normal maps work. In the video I'm only painting black and white maps as the bump, which is like a lesser normal map.

Where did you get the baked normal map from?

Answer 2 · 2019-03-01T01:11:18Z

r

replied March 1, 2019 1:11am

I baked the normal map from the hi poly version onto the lo poly version. I followed the steps in other CG Cookie course.

Answer 3 · 2019-03-05T14:41:34Z

Kent Trammell replied March 5, 2019 2:41pm

But this course didn't feature hi-poly model baking to lo-poly...

Maybe you're not referring to this course specifically, but just as an example. So perhaps you're trying to add additional details to a normal map via painting bump in the viewport. I think that can technically be done to a degree, but not with Blender 2.8 afaik. Try it with Blender Render in 2.79.

What you need to do is setup separate bump and normal textures in your material. Set the baked normal to influence the Normal channel (in the geometry section of the texture influence panel) then add a second "bump" map (black and white) to also affect the normal channel. Then you can paint white and black values into that bump map and they should appear combined with your normal map.

Understand though they they could end up fighting each other. It's a bit of a tricky thing you're after. Good luck with it though!