Resumable render returns number of lights error

[SonyBoy]

I've been using resumable render a lot recently, stopping and starting renders where necessary to complete other tasks. I've often got this error message, even when the number of lights in the scene most definitely has NOT changed:

// Error: V-Ray : -1: Number of lights is different

This is in a scene where actually some lights are animating on, but the frame in question is most definitely the same as the one that the render was started on and is the only frame being submitted to render.

[Dimitrina.Milanova]

Hello,

Is it possible for you to send a scene, with which you are able to reproduce this problem?
Also, with which V-Ray for Maya build are you reproducing the problem?

Аnother thing I need to ask are you sure that there are no changes to the scene, such as the number of lights in the scene that you are trying to render?
Have you tried to delete the vrprog/vrimg file from the folder you have set the project to and then render again (without changes to the scene, in-between the resumable rendering)?

Kind Regards,
Dimitrina

[SonyBoy]

"Have tried to delete the vrprog file from the folder you have set the project to"

I'm not familiar with this file nor can I find it.

I'm using Maya 2020.1 and Vray 5.00.20.

I'll send a test scene if it occurs again. There are the same number of lights on the frame in question, or should be.

[Dimitrina.Milanova]

Hello again,

With Bucket rendering, an additional .vrimg is written to temporarily store the data from the completed buckets.
With Progressive rendering, an additional .vrprog is written to temporarily store the data from the completed progressive render.
When you resume rendering, V-Ray will read the .vrimg file or .vrprog file, to determine which buckets still need to be rendered and continue to calculate what is left to complete the image.
You can find those files in the "Images" folder of the project you have set the scene.

It is very possible that this error you are getting is due to some changes of the lights in the scene after the first render and the second (the resumable rendering).
You can always check the tutorial from our documentation here too.

Kind Regards,
Dimitrina

[SonyBoy]

Sorry, I misread your message (your previous post also mentioned the "project" not the "images" folder so I took it to be a global file).

Deleting the vrimg file (I am rendering with buckets) of course clears the problem. But that totally defeats the purpose of resumable rendering in the first place.

So, this is at the crux of the entire issue.

[Dimitrina.Milanova]

Hello again,

Our developers are still looking into this problem.
Another thing I forgot to ask is if you reproducing this problem only when rendering in Maya, or you are using DR?

Kind Regards,
Dimitrina

[SonyBoy]

Circling back on this and yes I am using DR and have found that this problem is occurring when attempting to add the local machine back into the render pool. That is, rendering with resumable render turned on but with "Use Local Machine" checked off initially, then stopping and restarting the render with "Use Local Machine" checked ON will generate this number of lights error.

EDIT: In fact I have now seen this error triggered by simply toggling off Use Local Machine on a render that was started with it on as well. This is with only two machines. This is a bug.

[SonyBoy]

Any feedback on this? Simply adding or removing a machine when using DR into the framebuffer consistently generates this error and prevents renders from continuing.