Hello,
Im using simple material setup with two sphere masks (one on actor, second on camera)…
If im using both masks together, it causes shadow problems as shown in video:
If i delete one mask (but that bottom mask, thats broken), then everything works properly (im using dither opacity mask)… I dont know whats with that but that nodes are broken somehow… (edit: all stats at both masks are same… only location of creating mask not)
You are adding two sphere mask. Maybe you should clamp that value between 0 and 1.
I dont know how to clamp that values, but i tried to lerp them… It worked but unfortunately it caused another problem with rendering (ghost effects, i can turn them off with lower AA but then it doesnt looks well)…
Strange is, that two masks worked fine before i rebuilded lightning… also they worked for translucent material well (but not tested yet how after rebuild)…
I have plan C with cylinder mask but i wanted to solve these two masks…
There is clamp node. Default values are 0 and 1. Just use that.
Could you please tell me where to connect which pin? 
Im still material amateur and dont have idea how or which value to clamp.
x -> Clamp -> 1 - x -> Opacity Mask.
amazing! clamp 0 - 1 did not worked, bud 0 - 0,99 works perfectly how strange stuff…
so this is SOLVED
Its not strange, its that you aren’t understanding the math of what is happening.
The sphere masks output a value of 0 outside the mask 1 inside with a transition zone controlled by hardness.
So if you have two sphere masks overlapping you’ll have values from 0-2. Then when you subtract that from 1 you get a range of 1 to -1. Negative values plugged into just about anything in the shading system result in anomalous, often unpredictable effects.
Clamping the values to 1-0 gives you transparent to fully opaque.
I am glad you solved it.
