Black Pixels in VRayDirt + VRayExtraTex Renders in 32-bit Files (NaN Pixels?)

[alienboy]

I keep experiencing random black pixels while using VRayDirt to produce ambient occlusion and rendered as a VRayExtraTex render element, this only happened in 32-bit files (in both raw VRImg and EXR exports). Those pixels are persistent in Photoshop comp, I can't paint them any other color or using Stamp Tool to eliminate them.

The only workaround, previously, was paint the layer in 16-bit or 8-bit mode and copy it back to the original 32-bit document.

I later on read somewhere in the forums about the NaN pixels, and found out that those black pixels do have strange values read by Photoshop ("--2147483648"). Hence I found another workaround which is to throw a Curve layer, as Levels layer won't work, on top of the problematic VRayExtraTex layer and paint on top of the black pixels.

My questions are:

1. How to solve the issue and have V-Ray render the ambient occlusion/VRayExtraTex correctly?
2. Why the Levels in Photoshop won't clamp the pixel values, but the Curves will? (sorry, this is a Photoshop question, but I hope it will help me understand the process more)

The software versions that the issue is experienced with are:

• V-Ray 3.6/4.3/5.0
• 3ds Max 2018/2020

Thanks in advance!

[Joelaff]

Have you tried the Area image filter?

Also, I don’t use PS for floating point stuff much (use Fusion Studio). However, I wonder if those pixels have bad alpha values. If you turn your base layer into a true background layer do you still have trouble painting over them then?

[alienboy]

Have you tried the Area image filter?

Also, I don’t use PS for floating point stuff much (use Fusion Studio). However, I wonder if those pixels have bad alpha values. If you turn your base layer into a true background layer do you still have trouble painting over them then?

What is the area image filter you've mentioned, is it in V-Ray or Photoshop?

I've tried what you said and I can confirm that it has no alpha value issue, no matter I put a layer on top or underneath it, those pixels won't change to any other colors.

Maybe it has something to do with NaN pixels? Here's the value of the pixels:



I'd rather I fix this issue in V-Ray render then in Photoshop.

[nikoleta.garkova]

Hi alienboy, can you please forward this scene to support@chaosgroup.com and if needed, include steps to reproduce the issue. Make sure to mention this thread in the description, thanks.