Cleaning up glossy reflections

[beestee]

I need some advice. I am in the middle of applying materials to this scene and I am having a little trouble with my glossy reflections, what would be the best approach to clean them up? Right now I have the reflections set at 8 subdivisions, and my natrual inclination is to increase these per material. However, I am now a little more aware of VRay's other settings including the global subdivs option. I am curious if it is better practice to keep my materials consistent in subdivs and just raise the global setting, or is it better to maintain different levels of subdivs per material?

I am also aware that I need to raise my image sampling...but I am saving that for after I get all of the materials done.

Thanks

[beestee]

What causes the circular shapes that are appearing on the blue wall?



EDIT: I think I may have found the culprit, but not necessarily a fix. The "cutoff" setting in the material's options affects these shapes and nearly elminiates them when set to the lowest "0.001." What else could I adjust?

[PIXELBOX_SRO]

your reflection falloff is to sharp.....in vray material (options rollout) u need to set the cutoff to 0.001

[m_hinks]

this cutoff value seems to be getting a lot of interest at the moment. Should the value be set to 0.001 as default to stop this?

[Clifton Santiago]

I've never experimented with the cutoff value...

I always set my glossy reflection Subdivs at 24 and my Global Subdivs multiplier to 8 to avoid the reflection noise problem (for finals at least).

[beestee]

It seems that the cutoff paramater is partly responsible...but it is only in the specular highlights that this is affected. If I set up the material to not show speculars I can get it to look just fine. So for future reference if anyone runs into this, they can set their highlight glossiness to 1.0 to get rid of it in the problem material.

I am still getting a little noise at 16 subdivs, so I am going to try 24 as suggested.

Thanks everyone

[tricky]

Nowadays I leave all subdivs at a material level at their default, 8. I control all quality by using the rQMC antialias settings.

[m_hinks]

I agree with Tricky, leave all material and light setting as default, control the whole image quality through the AA, as per cpnichols latest tutorial. Its very adaptive and quicker.

[beestee]

I need to watch that tutorial again.

[vance3d]

I've had similar issues with vray lights and what was causing it in my case was the sampling cutoff level. The default of .01 gave me the circles, setting it to .001 made the circles disappear.

V Miller

[beestee]

My lights are set to default 0.001 but it is allowing me to change it to 0.000...I didn't realize the same setting exists in the lights as well, thanks for that! I will run some more tests when I get the chance on Monday.

[beestee]

Okay, my problem is directly linked to the cutoff option in the VRayLights in my scene and glossy specular highlights on a dark material. If the cutoff is set to 0.001, the circular artifacts appear. If the cutoff is set to 0.0, the artifacts disappear. If I have the cutoff of the lights set to 0.0, and the cutoff in my material set to the default 0.01 the artifacts are still gone. The artifacts are only occuring in the specular highlights and not the standard reflections, even when they are set to a rather low glossiness.

I am starting to wonder if perhaps this issue is coming up because of the adjusted gamma settings messing with the way VRay and MAX are designed to work by default. In most cases where this is becoming visible, it would seem that the problem would not be visible using a default settings workflow.

Either way, at least I know how to avoid the problem for the time being, and perhaps this information can be used to help isolate the issue so that maybe it can be addressed in a future release of VRay

EDIT: Cutoff in the material is affecting the speculars, but in different areas...it does disappear when I set the VRayMtl cutoff to 0.0 though.

[Raytonium]

I agree with Tricky, leave all material and light setting as default, control the whole image quality through the AA, as per cpnichols latest tutorial. Its very adaptive and quicker.

Where can this tutorial be found?

[VKNT]

You can buy it on gnomonology. Pretty cheap at 7$.
http://gnomonology.com/tutorial/62

[Raytonium]

You can buy it on gnomonology. Pretty cheap at 7$.
http://gnomonology.com/tutorial/62

Thank you.