Arnold Round Corners issue

[Dantetron]

Hello folks.

Running into a lot of noise issues when trying to utilize the Arnold 'round corners' shader.

Even when I crank up the samples to 100! I get random noise throughout all my materials.

Super-sparkly on random edges. 'Round corners' is an incredibly important tool when you can't chamfer your entire scene and makes a scene look much more professional.    Can we get it working?

Thanks!

[oliver]

I made some quick tests and can't see more/less noise with/without applied Round Corners. The only scenario where I noticed something matching your observations is when I set the corner radius to a very very small value (like the default 0,01).

left: no RoundCorners right: with RoundCorners

[CiroCardoso3v]

What happens if you reduce the specularity?

[Dantetron]

Thanks for your input, Oliver and CiroCardoso3v.

Both of you are on the right course.  The round corners shader is working very well on the objects when the camera is close to the object. But it falls apart as the camera zooms out.  So the "size" relative to the camera is part of the problem. And, yes, the objects are metallic so that's only enhancing the problem.

To solve the problem I'm forced to animate the round corner radius to zero as the camera pulls out.  An hour I spent that seems like the software should be able to handle on its own.  Nothin' more fun than spending time on workarounds! 

[CiroCardoso3v]

That is a bug for sure. If you can share just a bit of the geometry as an example, or create a short screengrab of this, I can report it directly to the Arnold Developers. 

[oliver]

The Radius-setting is strange anyway: it does not take the set scene-units into account. 

The default setting of 0,01 gives the same result in Centimeter-scale and Meter-scale.

When my scene is set to a certain unit scale I expect the setting to be measured in that unit! Changing the unit-scale while working should change these kind of settings as well.

[CiroCardoso3v]

That is true. Could be based on your units. 0.01 of what? Going to make that suggestion.

Although I guess the value is relative to the object you are working on. If you change the scale, the round corners don't change.

[CiroCardoso3v]

Ok, I guess I need to start checking documentation more often.

https://docs.arnoldrenderer.com/display/A5NodeRef/round_corners

The round corners is done in object space, thus not having real units. It will scale according to the object size.

@Dantetron 

Check the option Object Space

Set object scale to false when you want to use a world space radius so that geometries with different transform scales get a uniform world space rounding.