Maybe a solution for DR bug

[seq]

Hi,

during several productions in the past 2 years, we had that phenomenon that same buckets looks different from the others, when we use DR + IRmap + LC.

We had sent several scenes to Chaosgroup and had tried many different settings, but nothing had helped.

Yesterday we had that bug again and I accidentally I saw the IRmap advanced option "Randomize samples" and after turn it off, I could not believe it, the image renders fine.

Now my question: Can this be the true reason? And how would an animation be affected when we disable this option?

Thanks for any input.
Lars

[vlado]

It would be very odd as the irradiance map is synchronized between all the machines, so they should be using the same samples, regardless of the randomize option. The only case where this doesn't happen is if you use the "bucket mode" of the iradiance map.

Unfortunately we could not reproduce this effect with any of the scenes that you sent, but we are still keeping an eye for it.

Best regards,
Vlado

[seq]

Thanks Vlado. Never ever had used the bucket mode.

See if I can can send you the current scene, but I guess it won't help. Maybe it has something to do with our configuration or network or ... ?

[vlado]

It could be a network issue if parts of the map fail to get transferred to the render servers; a more stable approach would be to first calculate the map, save it to disk, and then use the saved map to render the final image.

Best regards,
Vlado

[Komposer]

Hi,

maybe I am wrong....
But here in my network, I had massive probs with automatic IPs.
The results looks realy like ur buckedprobs.
After setting every machine to fixed IPs everything worked fine.

Best regards,
Jörg

[seq]

Thanks Jörg for the tip. But it seems that also all machines get their IP from a DCHP-Server (Switch), they always get the same IP and the master machine can find the DR clients without problems. At least it seems to be that way!?

@Vlado: Hm, isn't it so that all machine (master and clients) render the IRmap together and afterwards the whole map is saved on the master disk and then is distributed to the clients (Sending 172 bytes of irradiance map to client_1). So what would be the difference in your approach?

And when our problem is a network problem and parts of the map failed to get transferred, shouldn't be there any error message?

[vlado]

@Vlado: Hm, isn't it so that all machine (master and clients) render the IRmap together and afterwards the whole map is saved on the master disk and then is distributed to the clients

The map is kept in the RAM of the client machine and then it is distributed over the network to the render servers; the disk is not involved anywhere in this.

(Sending 172 bytes of irradiance map to client_1)

172 bytes seems way too little (this is literally just a couple of samples). It might explain the issue...

So what would be the difference in your approach?

The difference would be that the map is saved to disk explicitly and each server reads it independently of the client machine.

And when our problem is a network problem and parts of the map failed to get transferred, shouldn't be there any error message?

Ideally, yes. However like I said, 172 bytes mean that there is very little information that is transferred, so it could have gotten lost along the way.

Best regards,
Vlado

[seq]

Sorry, Vlado, this was a misleading information. This was just the last line. A lot more bytes get transfered to the clients.

I'll try to first save out the map.

Really would like to know what sort of network error this could be, because the network is fast (Gigabit) and has not much traffic.

[snivlem]

Try using UNC paths, V-Ray dr services doesn't work with mapped network drive names.

[seq]

Thanks snivlem, but for this project all textures are locally available for each render client.

Strange thing is that the error appears only in certain area: On the attached image only on the glass shader. When it would be a general network error then the error should appear over the whole image, or?

But it definitely has to do something with DR, because if only one computer renders the image it is fine.

Very annoying!

[vlado]

Do you have fog in the glass shader?

Best regards,
Vlado

[seq]

Yes. Why do you ask?

[Neilg]

I see this problem all the time. Different machines render the fog as if it's at a different scale. Never found a fix, just started tinting it in post.

[seq]

Okay, thanks. I'll try that. And I will check if fog was involved in the scenes that had shown this error in the past.

Report back.

[vlado]

Some users have reported this error where the fog might render differently. This seems to be an issue for both V-Ray for 3ds Max and Maya, which use completely different shaders internally. For the moment, I have no idea why, but we are looking into it. BTW is there any difference in the processors of the machines that you are using?

Best regards,
Vlado