Lights - How many we can use today?

[Dionysios.TS]

Hi all,

I know in the past we had a limit with the number of lights we could use in a scene. Was group of 256.
Is this changed today or the limit is the same? I have a project with thousands of them and everything got so slooooooow....

Just to know before I start doing some editing and figure out other options.

Thanks in advance,

Dionysios -

[maru]

If the adaptive light solver (at the top of the Performance tab) is turned on, it is always used if there is more than 1 light source.

If it's turned off, we use two different solvers: one for less than or equal to 255 lights, and one for more than 255 lights.

You can try with the adaptive solver on and off, but generally, it should be optimal with the solver on.

If you could share this problematic scene with us, we could probably see if it's something that can be optimized.
Also, please be sure to use light-emitting Corona Lights / Light Mtl vs self illumination vs Light Mtl with light emission off correctly: https://coronarenderer.freshdesk.com/support/solutions/articles/5000515603

[Dionysios.TS]

The adaptive solver was on and this is the reason why I asked.

In total I had about 40.000 lights, I know, too many and they were distributed in 2 skyscrapers, 150m height each one. All of them were instance copies of 1 Corona Light.
The render was very slow to start, about 8/10 minutes considering a lot of forest objects and proxies in the scene. Once started the rendering speed was abnormal.

I created instance copies, groups of maximum 250 lights each one and things got much better. Render times returned to normal.
Probably 35.000 lights are a lot, personally I don't know.

Thanks for getting back!

[maru]

With so many lights, if the lighting solution does not have to be super precise, or if there are no interior shots, I would definitely recommend simplifying the setup. For example: using a single flat plane with a transparent Light Mtl with "emit light" disabled for a grid of lights on the ceiling. Then adding just one / few lights per room to fake the illumination. It's just a general example, as I am not sure what exactly your scenario requires.

[Dionysios.TS]

Thanks!

Usually I do what you suggested but for that scene I had to do that approach for technical reasons.
Probably all those lights were too much. This is why I asked. :)

Thanks in any case.