[Switch Toolbox] How to properly convert yellow/orange normal maps to blue

[Fawfulthegreat64]

Ripping Switch models using Toolbox usually results in yellow-colored normal maps.

For years I've simply inverted them and assumed problem solved, since it appeared to now have the proper colors.

But now I directly compared my result from that method to a rip done by a staff member, and it is different.

This is the raw image I get with Toolbox.


Inverting it gives me this:


However, it should look like this:


This suggests that there's a more complex conversion process than simply inverting, or there's some setting in Toolbox I need to change. Google is yielding me less than nothing on this matter. I also wasn't sure whether to post this in the models or textures section, but I went with the former because this is for the purpose of a model rip.

Found a solution in Toolbox: for some reason the normal maps will have their Blue channel set to zero. If you change that to Blue, the image is fixed. I found this solution in a game-specific tutorial but I think it should be searchable on its own because it applies to every game I've tried to rip from using Toolbox, and I definitely would not have figured that out without a lot of trial and error.

An even simpler solution: uncheck "use texture channel swaps" when exporting.

[Sir Teatei Moonlight]

From your edit you've found a solution, but I'm posting this explanation anyway.

The premise here is that normal maps don't actually need the blue data saved in the image, because you can just recreate it from the red and green (since the idea is that it's a unit vector). The BC5 format is designed specifically for this, and any competent extractor will offer the option to auto-calculate the blue channel for it when extracting. And if it doesn't, there's probably some tool out there that will do the conversion for you.

[Fawfulthegreat64]

That's interesting. There's actually an even simpler solution in Toolbox that I didn't know before, and that's to uncheck "use texture channel swaps" when exporting.