Jumping back into this thread. If you haven’t yet tried or successfully rounded the corners using V-Ray, as opposed to rounding corners in the model. The advantage of this method is that it won’t add geometry to your model and will make it easier to edit since it preserves the 90 degree connections. Here’s how to do it:
Start by adding a new material from scratch. Choose ‘Bump’ from the options
Then switch your mode to ‘Bump Texture Channel’
Under the texture slot…choose ‘Edges’:
Adjust radius of edges here:
Add your wall texture/material to the new bump material under the ‘base’ section:
Lastly, be sure to apply (or reapply) your new ‘round edges’ material to your surface(s). Be sure to copy or duplicate the material and change the ‘base’ material/texture for different surfaces in your model. That way you only have to set this material up once.
Let me know if this helps.