I am looking to apply a patina texture similar to the below picture to basically a cube. When I try and apply similar textures to large flat surfaces they don't look very good. I'm guessing it is because the materials are using a curvature material to generate an opacity map to map the patina vs the metal color. I thought of a workaround by exporting a UV of the cube shape and manually creating a mask for the image. If anyone has a better idea for quickly doing this let me know.
(https://www.keyshot.com/forum/index.php?action=dlattach;topic=11546.0;attach=30614;image)
Example of patina metal on a complicated model
http://imgur.com/a/QABBy (http://imgur.com/a/QABBy)
What a cube looks like with a similar texture applied
I'd tackle this by starting with a bump texture... then using either curvature or occlusion (as opacity as you mentioned) to show the underlying metal material.