I want to create a puddle with a soft edge. I think if I drive the opacity near the edge of the water, a hard intersection edge will disappear.
However, when I tried linking curvature node to cutout opacity, the puddle had a weird black edge without transparency. Is it a bug? or I did something wrong. I am sure opaque in Arnold tag was disabled.
And I inverted the curvature to see what would happen, it looked correct.
There are some screenshots that can be switched to see the difference, The third picture is two shaders mixed, it's the effect I want.
Here is C4D file: