GI Flicker with animated Sun/Sky system

[matteley]

Hi, I've been experiencing quite lot of flicker when animating the vray Sun system. Basically my scene consists of a car interior lit predominantly with the sun/sky system, the sun is then animated to give the effect of a sunset.

I have several additional rectangle lights to boost the interior lighting but have experimented with and without these but the flickering still occurs. At the same time my camera is animated with a small amount of movement.

I've not experience GI flicker to this extent with Vray in previous animation jobs so I'm wondering if this is a floor to the sun/sky system, or if I'm simply expecting it to do something it wasn't designed to deliver.

I'm using adaptive DMC: min:1, max: 10, threshold: 0.003.

My GI settings are as follows:

Primary bounces: IR Map, High animation, subs: 50, interp samples: 60, interp frames: 2. All settings set to animation. Have baked the map using animation prepass, then loaded to animation rendering.

Secondary bounces: Light Cache, subs: 500, sample size: 0.02, Mode: Flythrough

Please let me know if I can provide additional information.

Any advice for achieving a flicker free sunset would be very much appreciated. Thanks in adv
Matt

[aweidenhammer]

Firstly, turn the visibility of the sun off. I've seen that produce noise, and it could thus produce some flicker. But I'm guessing that is not the source of GI flicker. Short of that, I've had recent success with this technique to eliminate gi flicker:
http://www.spot3d.com/vray/help/150S...ials_anim2.htm

I often render a small sequence with all the reconstruction passes on (diff, spec, refl, refr, GI, sss, etc) and look at each channel specifically to find out where my noise or flicker is coming from. Assuming you know the flicker is a GI problem, the above technique can definitely help. You might also get better results from a pure brute force method.

Given your current settings, you could also stand to use more subdivs on lightcache. But that probably won't completely eliminate flicker when most of your image is lit by ambient and bounce light.

Andrew

[matteley]

Hi Andrew, thanks for your response. I've turned off the sun visibility just to rule that out but the guide you mentioned there was very useful so have adapted my settings as it suggests. Looking at my GI render element pass it is the GI that's flickering. Hopefully will have something that doesn't flicker rendered out by tomorrow morning. Will post back with the result. Thanks
again
Matt