Vray Timelapse / different times of day

[runelore]

Hi,

 

I have an animation that I am creating in which the animation goes through various times of day with the sun rising and setting (linked to Max Daylight system). So the sun is animated though the scene, following the time of day.

 

Unfortunately I am having a lot of trouble trying to set up the rendering system for these sequences. I am using irrad map (primary) and Light cache (secondary) as my GI bounces. The problem I have is that light cache is only computing the light cache based on the lighting of a single frame, but the lighting changes in intensity, colour and ambience though the whole sequence. So I need to be able to pre-cache the animated lighting so I dont get flickering when rendering the final stills.

 

An example... If I calculate my light cache using a frame that has the sun at its highest point, the whole sequence comes out with the lighting as if the sun is always there, even though it sets. the same is vice versa..

 

I need a way if storing the lighting through out the whole animation. I thought of using irrad map as primary and secondary bounces, but that isnt working very well.

 

I have no problems with anything else, just getting the lighting to chance through out the sequence properly. It does render fine if I dont pre-cache the light cache, but of course I get artifacting and flickering when rendering the animation.. How do I pre-calculate an animated light?

 

apologies if this is a difficult post to understand, I have explained it as well as possible..

[Chad Warner]

We just finished an animation doing this same thing, and I ended up doing the irradiance map and light cache frame by frame, but I was also going for the kind of "jerky" effect that you get with timelapse. We also had a static camera, so the only thing that moved were the sun and some objects.

[ihabkal]

As Chad said, frame by frame, raise the quality to reduce flickering to a minimum at the cost of more render time. IRmap as I think of it after seeing the Gnomon tutorials, is a 3d scene that is on top of your 3d scene, comprised of dots that are big and small, these dots tell the software wehre light is or isn't. so for a thousand frame or one frame, the IRmap is the same data, only with moving cameras you sample hidden areas that get revealed as the camera moves.

[BrianKitts]

I've done some testing with this as I'm going to be doing an animation coming up where we are doing the same thing of timelapsing day to night.

 

I leave the lightcache set to single frame, 800 subdivs, then run the irradiance in animation(prepass) mode for every frame, that way the lightcache info gets saved into the irradiance map (remember the light cache info is used to approximate the irradiance map at calculation time).

 

Then after you have the irr precalced go back and render the animation with Lightcache still set to single frame, and the irradiance set to animation(render). Right now Im using the blending set to 2 frames for the IRR map.

 

Seems to be working pretty well. You get the speed advantage having the lightcache calc, even though it's running at every frame,it's alot quicker than using brute force for your secondary light bounces. Then frame blending of the animation irr map smooths the GI changing throughout.

Edited January 12, 2009 by BrianKitts

[runelore]

Many thanks for your responses.

 

the above suggestion works like a treat. Shows how much attention I pay, I hadnt even realised that they had added the new animation (prepass and render) modes to the IR map calculation.. lol

 

anyway, many thanks again for the help and you have made my day !

[Guest andremarca]

Hi guys.

 

I had just the same problem and tryed Brians solution. It worked, but i'm getting some light splotches in places i souldn't... If i render them with animation (prepass) and animation (render) they are there. If i render them in single frame with the same IR settings they are gone... (using the same lightcache settings for both)... This is just killing me.

 

Is there a way to render this frame by frame in single frame mode without getting flickering? I have a nice farm at home (4 phenom 2 940 quad cores) and could get away with that...

[Nic H]

if you have time Brute Force / LC (single frame) will give you good flicker free results, you just need to adjust the subdivs and dmc sampler to get rid of noise (or find an acceptable level of noise)

 

having brute force primary really helps bring out details where things meet and pass by each other.i had to use this method recently on a animated interior with animated timeplase sun, camera, and objects. (worst case scenario) no other method would work, in the end 1280x720 frames were taking 30 mins on a dual quad machine and thats with alot of glossy reflections and smooth aa.

[Guest andremarca]

That's just my problem... Exterior Timelapse, moving camera, moving objects... I'll give Brute force /Lc a go tonight and see how it goes. I've tried everything without any luck... Single frame IR with High (animation) changed the AA, changed global Sub, noise threshold... and nothing works. I even thought it could be a material problem with the cars outside and the high gloss materials reflecting... There has to be a solution... There's always one :)