How to add rounded edges effect to materials?

To add rounded edges to materials, add a CoronaRoundEdges map, and plug it into the material's Bump slot:

The CoronaRoundEdges map simulates rounded edges on materials, however this is just a shading effect, and the geometry is not really chamfered. This effect is useful for adding detail to geometric forms such as machine parts, and to add subtle chamfer to walls in interior visualizations. 

Corona Renderer offers two modes of the round edges effect: 

  • Fast - this mode renders faster, however it does not support any advanced features such as different mesh elements affecting each other, different meshes affecting each other, and includes/excludes. This means that the edges will be rounded only withing a single mesh, and if some other object is touching it, they will not be rounded in that place.

  • Precise - this mode renders slower, but it allows for such advanced features as affecting different elements inside a single mesh, affecting different objects by each other, and includes/excludes. This means that the edges will be rounded in the places where different elements o f a single mesh are intersecting, and where different objects are intersecting. The includes and excludes allow the user to specific which objects should be considered for the rounded edges effect. 


1. General example showing the Corona Round Edges texmap:

The objects at the top are using the CoronaRoundEdges map. The geometry edges are actually hard.

The bottom objects are actually chamfered. There is virtually no difference between the appearance of the objects which are chamfered, and the ones which are using the CoronaRoundEdges map. 

(click to enlarge and see more details)

The wireframe view shows that only the bottom objects are really chamfered.

2. Fast mode:

Note that the edges are not rounded in places where different objects intersect. 

3. Precise mode

Note that by default (with the "no excludes" option), every object affects each other so the rounded edges are visible in the places where different objects intersect, and even where the objects intersect with the ground plane.

4. Precise mode with the ground plane excluded

Note that the edges are not rounded where the ground plane is touching the objects.


The rounded edges are showing in places where I wouldn't expect them!

Possible solutions:

  • Make sure that there are no errors in the geometry which is using the rounded edges material (e.g. that there are no overlapping faces, that edges are not doubled).
  • It is possible that the rounded edges are "leaking" from other objects. In such case you can use the "Same object only" option to prevent other objects from affecting the rounded geometry. 
  • If some issues are still visible, try changing the mode from precise to fast (or vice versa), and try toggling the "Legacy" checkbox on and off.