Hello,
I don't know how to combine two normal maps together in MaterialX, is there any node to do this? I've seen some examples of how to make a mathematical implementation in Blender that could probably be translated into materialX, but I want to make sure if this is the only way to make it work.

Thanks,
Dawid

mtlx is missing the quaternion and matrix math operations that would make this doable in the usual way. However, you could implement the component-wise scalar multiplications and additions that compose the higher level matrix math.

I`m also tryiong the blender tutorial on houdini but it seems there is are some probems or i made some mistakes.

My conversion into polar coordinates seems to have a mistake in it as the all the values seem overly saturated

If you are using a triplanar good chance the result will be incorrect due to computing the tangent space in a triplanar world...

In Karma , you could decomposite all your Normal vector 3 into their components XYZ, then doing an addition per component for X Y, combining back to Vector with Zres=Z1. Then normalizing, and divide by 2 at the end.

That should give you a correct result.