I cant render scene when i connect roughness map to pbr node or disney shader node.nothing happens just empty screen.
You can connect roughness maps to the Disney shader roughness input but you have to use the
Output Single Channel or convert the color output from
Output Color via
asLuminance to grey-scale.
The reason is that the roughness input node expects a floating point value and not a color. The Disney shader can not know which part of the color value (red, green, blue or all together) should determine the roughness.