VrScans with DR: Differences between buckets

[kosso_olli]

Hey, I am having problem with some VrayScannedMtl in my scene. I get subtle differences in my render between DR buckets. Please take a look at the screenshot.
The thing is that the VrScans are found by every DR node, otherwise the buckets would show no texture at all. There is no HDR in the scene. For every render the pattern of failed buckets changes, it is completely random. Also, the clients affected change with every render. The belt restraint doesn't even have a VrayScannedMtl assigned, but I assume it is reflecting the seat, which has.
I thought it might be a license problem, but we have 22 licenses for VrScans, but I am rendering on only 11 clients.
Honestly, I tried fixing this since Friday, but I am running out of ideas.

Max 2017, V-Ray 3.60.03

Regards

Oliver

[dinko.dimitrov]

Hey Oliver,

We will investigate this and will let you know.

Cheers,
Dinko

[Ivaylo Katev]

i suppose you are not using the defoult max lights (they are not present in the DR slaves) , so excluding this possibility the most common reason for DR difference is different vray/plugin versions on the slaves or the work station.
we would be able to give better suggestion if you give some additional info:
- how many dr slaves you have?
- what happens if you disable the work station rendering and use only the slaves?
- how it looks if you render only on the work station?
- the build info - what is the vray revision, i mean the number at the and of the vray archive file

[kosso_olli]

Ivaylo,
here are the answers to your questions:

- default lights are off
- I am using 10 DR slaves in total
- When disabling and rendering only on the slaves, the result is the same: I get random dropped buckets. Around 3 of 10 machines are producing dropped bucket, each render it is different machines.
- When rendering with my workstation only, the result is as expected.
- Build info: As stated before, V-Ray 3.60.03. Checked that a number of times, the render slaves are all exactly the same. Same version of V-Ray, same plugins etc.

Also, here is another image. It looks like the nodes are rendering 3 different versions of the same images. In 3 different brightness levels.

[Ivaylo Katev]

ok, but when you render only on the work station which one of these 3 versions is the correct one?
one more question that can be very helpful - can you switch on the DR bucket render element ( it shows the per bucket slave info) and post the result here?

[kosso_olli]

Sure,
here you go. The correct version is the darkest of all.
Another thing I observed: The buckets appear only in the Reflection Render Element. Lighting is clean.
The DR bucket is not really helpfull here, because as I said: Each time I render, a different client is causing the buckets. It is totally random. However, please find attached:
lighting, reflection, and DR bucket. Each from the same render.

[nikolay.kusht]

I would recomend to check the following general DR solutions and see if they could help:

- Check the V-Ray log file for any errors.
- Make sure that you have installed the same V-Ray version on all machines.
- Check if 3ds Max version installed on all of the machines is the same.
- Please make sure that the Windows regional settings "Additional settings" "Decimal symbol" and "Digit grouping symbol" have same setup for all machines.
Regarding the regional settings mentioned, please open Control Panel > Region and Language > Formats > Format tab ? it is required to be same on every machine. Check if there is a machine that differs from the others.
- Verify that there are no textures/assets that are not accessible from the render nodes. We would recommend using UNC paths for all textures /used in the scene.
- Another thing is to have the "Transfer missign assets" options under V-Ray Distributed Rendering settings window always checked and see if this helps.
- Furthermore if VraySpawner is registered as a service please make sure it uses an administrator account or start the Spawner manually.
- Check and see if the Gamma correction(Customize>Preferences>Gamma and LUT) is the same to all render machines.
- Lastly, try resetting your V-Ray settings(by switching to scanline or mental ray and then revert back to V-Ray) on this particular scene. Then try setting up V-Ray manually and make test render.

[kosso_olli]

Alright guys,
I have been using V-Ray for the last ten years. I am not a newbie, I know how to use DR and I have used it for hundreds of images without problems.
The solutions you posted might be fine for a general DR error, but this here is highly specific. I narrowed it down as far as I could, but I have to come to the conclusion that it must be a bug. Why should only the reflection channel show that strange behavior? If it was some missing asset, texture or whatever, the bucket would look totally different. Also, the fact that the appearance of the dropped buckets are totally random freaks me out. It is not the same machine each rendering, it is a different one every time.

[Ivaylo Katev]

i agree, this is a specific error and i think i have idea what causes it, but to be sure must reproduce the problem here. would you send the scene to our support?

[kosso_olli]

I will try to strip down the scene, as I probably can not send it as is because of NDA.
Let me check if I can still reproduce it with only the necessary parts.

[kosso_olli]

I sent the scene to you, Ivaylo. Danke!

[kosso_olli]

I can confirm that the problem is fixed in the current nightly builds. Thanks for the help!

[Ivaylo Katev]

just to introduce small correction - there are actually no nightly builds from the actual sources, so if you try to download the latest stable 3.6 builds the problem will be still present.
however, we will update the stable builds to include the latest fixes and new stuffs

[kosso_olli]

The problem occured today in another scene. I sent the scene to Ivaylo.
I tested both the official 3.60.04 as well as another plugin version which was said to fix the problem.
For now my company will stop using the VrScans because of that problem. I just don't get any consistent output with DR, which is a shame.

[Ivaylo Katev]

this is really bad
well, let's hope that your scene will help us to resolve the issue and prevent the same problem to the other users.