Small / far away lights disappearing and appearing in animations.

[JD3D_CGI]

I have an animation with lots of lights, and some of them seem to be appearing and disappearing during the animation.

I'm using brute force/brute force.

The lights are sometimes behind glass or water...

What can help fix this?

[vladimir_krastev]

Hi, thanks for posting. Increasing the resolution and increasing the subdivs of the image sampler should help. Please check this thread and this article. Some if the advice there may help in your case.
Try to increase the number of adaptive lights (the default is 8 ) and see if this helps. You could also send us the scene for review. Please if you choose this option try to simplify the scene as much as possible, removing everything that is not necessary for demonstrating the issue.

[JD3D_CGI]

Thanks - so it's not fireflies which are the problem, it's lights seeming to appear and disappear.
I have gotten to understand using the Sample Rate and Noise render elements and so I have 900000 samples in the scene - no noise.

It's more like Vray can't decide whether the light is big enough to render or not.

I just did a test with Full Lighting Evaluation and the problem went away.... but the render times were crazy.

Since I was using BF, presumably adaptive lighting doesn't work, and it reverts to light tree?

[JD3D_CGI]

So, I guess I am goign to have to send this file into you guys.

Just to clarify - I am NOT taking about fireflies, I am talking about entire lights changing their values between frames. See the lanterns in the background.

[vladimir_krastev]

I see, so the lights are not disappearing altogether but changing intensity. This looks like a whole lighting fixture, not a visible VRayLight. Maybe the materials used have something to do with the issue.
Send us the scene for review if you can not manage on your own.

[vladimir_krastev]

This issue is related to VRayLights with very small size and very high intensity. The issue is reported under VMAX-14310.