Hey all 
I am using a mask to blend one material with the other in my master material.
Sadly, the mask is using the UV’s of the mesh which does not give me any benefit.
The question is, can I use something else (e.g. absolute world position) to place the mask on the whole mesh
not over the UV?
In the images you see that world position does not work.
Any ideas?
Edit: I also get a float3 → float error message when I connect the mask to the alpha canal of the lerp (just at roughness and Ambient Occlusion)…
Hey, sorry that it took that much time 
I tried both with different results.
The first option with 0,01 multiplier and using the red channel works with the mask.
I can see an effect. After all it is not the effect I hoped for but it is a start.
The material should replace the other material but it just blends over in a bad way.
Anyway I guess this is cause I messed up the blending too?
I had some problems with the second option as I do not find " subtract object location RG add
Texture size / 2". Can you please explain or send an image what do you mean with object location RG and Texture Size?
This would be really helpful.
I added some images to explain what I mean.
There is one with that what I made out of each of your solutions.
One shows the example which isn’t really helpful I guess.
The last one shows how I blend those both materials, anyway the goal
is that the mask is saying where one material is shown, not blended.
Btw. next time I will test it faster