How to optimize this?

[miguelortega]

I have this scene which is taking 40-60 hours to render per frame.
It's geometrically not very complex but the refractions + many lights are killing us.
There's around 80 sphere lights. We have tried probobalistic lights but we get a lot of noise.
How would you guys approach this?. If we disable the glass shaders in front of the lights it renders much faster.

No caustics
No atmospherics

[yolov]

You could try and break the light/shadow links between the lights and the glass objects and run a test render.
Or lower the refraction depth of the glass to 2.
See if any of that helps.

[Mihail.Djurev]

You could try adding a V-Ray object property on the glass in front of the lights and disabling "cast shadows" and "visible to GI". If my guess is correct, that would speed things up without having a dramatic effect on the scene.

Best regards,
Mihail

[yolov]

I'd vote for Mihail's solution to be tested first since it's easier to set up than tweaking the light links.

[Neilg]

I'd have the glass not casting shadows or contributing to GI - invisible to all calculations except for reflecting things in the scene. Glass could also be switched off outright and rendered as a separate pass.

[bigbossfr]

Perhaps to see what we can optimize, can we have the log to see how many rays with have on each part on the render ? (shd, refrac....)

[Morbid Angel]

probably best to get part of this scene to support. Since you say there are no caustics and no atmospherics its a bit odd. What is creating that glow over the lights? is it in comp? There seems to be atmosphere there so I'm not sure...

Also what are your settings now? gi? etc...