The OSL shader actually work quite well. Taking a ‘shader’ approach is the best, because first, it doesn’t touch on the geometry, secondly, it’s problem free(because it doesn’t involve geometry). I’m shifting my focus on a shader-based approach. Does Blender Render has any access point where I can fiddle around the GLSL shaders and maybe bake off normals from it?
After some testing about the “bevel object” method, I’ve found a major problem. The default bevel operation of Blender does not follow surrounding topology nor is there an option to do so. Therefore, the baked normal map from the bevel object works perfectly where the topology was followed, but creates significantly visible seams around places where the topology wasn’t followed.
If the surrounding faces’ normal are not all pointing at one direction, the bevel object’s normal will also not blend in perfectly when combined with other normals. I consider this “Bevel Object” method a failure. Unless there is a way to custom bevel the edges following surrounding geometry and blend the bevel with any non-flat surrounding faces.
Nvidia’s MDL was implemented into Substance Designer and there was a ‘Rounded Corner Normal’ that achieves exactly the same effect of MODO’s rounded edge shader.