Find edges map

[JoachimArt]

I know one can use Corona AO map to mask out edges, but I find it very non-user friendly in many cases. Especially if you have some object with small degree changes in the corners and you want to make really strong contrast between white and black. I need to fiddle a lot with the map and also add multiple corona color correction passes and everything becomes very slow. And if you make any changes to size etc, the numbers you set up easily doesn’t work. It would have been awesome to have a “corona find edges map” which has a few options to combine with a map and choose falloff and strength the same way corona AO does.

[pokoy]

If I recall correctly the Rounded Edges map can be rendered as a color too, maybe it'll work better for you.

[JoachimArt]

that would have been perfect, but I'm not able to get that to work. THere's no such option that I can find, and placing it in a mix map does nothing.

[pokoy]

Hmm, I'm using a RoundEdgesMap in the diffuse channel and it works instantly. I'm on Max, if you're on C4D it might be different, don't know.

[JoachimArt]

You are right! Sorry! I added it in the mix amount and then it seemed not to do anything, But when I add it straight into the Diffuse it works! But I found out it works in the mix map as well, only that I need to increase the contrast a lot, something happens once its added as mix. But that will work better than AO in some cases, awesome, thanks a lot for the tip!

[pokoy]

It may need some color correction in order to get a sharper gradient, but that seems to work well, too, just checked.
Actually, I didn't realize until now how convenient it is for some stuff where AO doesn't cut it, so thank for coming up with the question, too :D

[JoachimArt]

Hehe. 
Yeah its very convenient! AO is very nice for Inside stuff, but its very hard to get sharp crisp edges once you want outside edges mostly.
The corona round edges one works great until you have a soft edge (beveled edge) then it breaks - in fact then neither round endge or AO works very well at all for beveled outer edges, so a custom map for more control on edges would be nice still I think. I solved it with Data Channel now, I feel I have better control there for outer edges.

[pokoy]

Yes, RoundEdges will only work on edges that share different smoothing groups, edges sharing faces with the same smoothing group will not show up. If you need a certain edge to show up, the solution is to solve this via smoothing groups.
What we still need is a curvature map, for some reason this isn't anywhere on the roadmap, though it's been requested a few times and gets mentioned regularly when AO limitations come up in a discussion.

[JoachimArt]

I agree, curvature map would be great. I assume it would be more useful than the AO map in general, I expect most people use the AO map for map text purposes rather than adding actual Ambient Occlusion. Of course its nice that have the ability to do so, but a true curvature map would be more welcome, at least for me. I hope it will be added to the roadmap Corona Team ;)