GI flickering

[mikeh]

I'm new to VRay so please forgive the basic question. I have made an animation that uses GI. The GI on the buildings could be seen to filcker as the camera moved past the buildings. I used the Irradiance map preset of "very low" for the animation to cut the animation time and set it for a single prepass. This got images to render at 110 seconds per frame. Total animation takes 24 hours. I could do test after test to see what settings would get rid of the flicker and give me fast times but before i do that i thought i would ask more experienced users for some insight as to how to best achieve this.
I'm using Irradience map primary and photon map secondary.
Thanks,
mh

[DanielBrew]

Hi Mike,

Have you read the tutorial for walkthrough animations on the help website?
http://www.spot3d.com/vray/help/VRay...ials_imap2.htm

It explains the basic work flow for producing a walkthrough from saved lighting calculations. The process is a bit more complicated than the method you have used but the results will be far better. Basically if the camera is the only object in your scene that moves then you can precalculate the lighting (GI) for the whole walkthough.

Oh and don't use any materials with interpolated glossies as these flicker as well in an animation.

Dan

[joconnell]

Heya mike,


if you're doing an architectural flythrough where the camera moves and the scene doesnt, you are best off using precalculated maps which won't flicker at all. Read this tutorial to get you going: http://www.spot3d.com/vray/help/VRay...ials_imap2.htm

If you are rendering an animation where objects within the scene are moving such as character aniamtion, you're buggered. There's no real way around this aside from not using GI and instead using standard lights to make your scene look like it's using gi. If you have to use GI, use quasi monte carlo for the primary bounce and light cache for the secondary - when it moves it'll be grainy rather than flickery which is often more acceptable. You pretty much turn up your light subdivs and play with the qmc sampler until you get the noise to an acceptable level.

[instinct]

did you render the irr-map per frame ? if so you shouldnt. you should pre-calc one irrmap in advance and re-use it to lower flickering issues.

As you mentioned buildings i assume we´re talking about ArchViz. You might want to check out Vlado´s Tut on doing Fly-Through Anims in the help section.

Regards,
Thorsten

[instinct]

Damn....you guys are fast lol...that´s what i call 3 ppl one thought tho :P

[DanielBrew]

Great minds eh?

[mikeh]

got it!...thanks. I had breezed past the animation tutorial without really seeing that it was significantly different doing aniamtion with VRay GI than what i expected. Now i know.
mh