tyCache render error

[XavierV]

Hello, I came accros this weird bug while using tycache and rendering on our renderfarm.

The lighting of the tyCache is different between the first frame of any machine and all the other frames that this machine will render next. When i render on local machine, I don't have any problem and the lighting matches the one of the other frames.
The problem can only be seen on some tyCache (the moss one) and not the other of the scene. 
The only solution that I have at the moment is to rerender the first frame of each machine while the job is on the farm so it's not a "first" frame no more. 

If you have any idea of what can cause this issue I would be glad to hear it. 

Thank you

[tyFlow]

I'm not really sure what would cause that, no. Are you rendering as instances or meshes?

[XavierV]

Yes I was rendering with Instances.

I have done some test during the day and it seems that the probleme were coming from the "Load instance materials" in the material overrides panel, and the lighting issue was cause by the opacity map not loaded by vray for casting the shadow (images in attachement). 
When I unchecked the "load instance materials" and apply the good material to the tycache, the render were good on all frame. There is still render on the farm but it seems that it's good.


Thanks

[tyFlow]

Is it possible one of your farm machines could not see the texture (ie, didn't have access to the shared directory)?

[XavierV]

Mm, I don't think so, because the opacity map is in the same folder that the diffuse and I know it's weird but it was only the first frame of each machine where the bug occurred.

If i have the time, I will try to redo the bug in a simpler scene.