imperfections on edges

[prince_jr]

hi to everone, and happy new year!

i don't know if there is already a topic for this...
i want to add some imperfections to edges of an object for a close-up render. for example a concrete wall, where the cement is missing in some places (broken off)
> see attached image.

1. i tried to solve it with a texture in the bump slot of round edges
    > didn't work very well / it wasn't satisfying enough, as far iim searching for a realistic look.

2. i tried to solve it with a displacement map and beveled edges.
    > the problem here is...the height of the displacement is the same on both, surface and beveled edge.
    > would be nice if there is a way to handle displacement separately. one slot for surface, one for edges ;o)

back to my request...
is there any way to accomplish this?

i thank you for your help and inputs.

[Cinemike]

You can always bevel your edges and instantly get faces to apply displacement to.

[rojharris]

Hmmm.. There should be a way to mask displacement using the AO filter set to 'outside'... however I can't get it to work... tried a few things but if I get anywhere I'll let you know.

[houska]

The AO shader is currently not allowed in the Displacement channel. There should even be a warning about that.

[prince_jr]

thanks for your answers so far.

@houska:
this methode is very time-consuming. i'm looking for a "global" solution by edge shader.

@rojharris:
okay, thanks for the hint.

@houska:
basically i'm doing architectural renderings (interior & exterior) > adding imperfections to edges would be a "killer"-feature in corona! :oD
would be on my wishlist for future releases :o) but i don't know if this will ever be possible...!?

so...how would you personally add imperfections to edges at the moment?

[Beanzvision]

I had a quick play around and came up with this. Feel free to tweak it how you see fit. :)

[prince_jr]

thx @beanzvision
i tried to tweak it. but as i tried on another object (for example 200x100x10cm) the shader is messed up (stretched).
i ended up by manually deforming the edges. it took too loooong... :o(

would be nice if there's an easier way to get such results in future.
i like the round edges feature and always use it. not only bump should work with it, but displacement, too ;o)