Render region and tiling region in FX maps?

gnoop

I am trying to make the rotation works properly in FX-maps . Not stretching in non-square textures. Adobe support says I have to use render region and tile region. basically two float4 values to compensate it.

I couldn't figure out a thing with how they actually work. Seems doing something totally random.

Have anyone ever managed to make something meaningful with those things?