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RCFX
08-11-2003, 04:19 PM
As Chriz said, I did the water effects for the worm capture sequence. Basically it was 3 emiters, a stationary one that did the bulk of the water, an animated one that did the up-front churning, and another animated one that did the lead spray. A subdived, fractally displaced plate was underneath so that bits of blue water could be seen. All of this traveled down a low-poly trench which was set as a collision object and was invisible to the camera. An additional emitter was used for the corner-turning scene to give me a bigger splash. All elements were rendered seperately and comped in AE. A sinle elemet could take up to 4 hours a frame, and that was using volumetric sprites. The first shot took 29 takes to get right.. Stills can be seen at http://www.hallofshadows.com/cod11.htm .

js33
08-11-2003, 04:31 PM
Hi Ryan,

Thanks for the scene description. I think we all wanted to hear that it didn't take long to render.:D Man 4 hours a frame for some of them. I don't have that kind of patience. 4 minutes a frame and I start to get ancey. So how many particles did you have total? I played around with immitating your scene and I got close but of course it never looked as good as yours. So you rendered 4 passes or so then comped them. I figureded it was comped as that many particles at once would definately bog LW down. Is there any chance of a tutorial?

Cheers,
JS

RCFX
08-11-2003, 04:41 PM
I meant to do this a a reply, not a new thread. Sorry about that. The renders were more like 1.5 hours average. I think it was the wave that swept over the camera that hit 4 hours. The decision to render in passes was made before I realized what a render hog this would be (though it was nowhere NEAR Ken's 7 hour a frame dust storm!). I liked comping in AE so I could tweak color, levels, and sharpness element by element. Plus it allowed me to mask out some stray particles that just wouldn't behave. I'm brand new to this board....a user saw some posts where I was mentioned and tracked me down thru imdb.com...but I wouldn't be opposede to doing a tutorial. Only problem was that the water took over a month to finesse and, being that it was a year ago, I doubt I'd remember any of the exact settings.

js33
08-11-2003, 04:54 PM
Hi again Ryan,

I'm glad you made a new thread as we might not have seen it otherwise. I understand about wanting to composite and the stray particles. It would take to long to render all in LW and also you wouldn't be able to change or adjust anything afterward.
I also use AE and render alot of things as elements for later compositing so I understand the workflow. A tutorial would be cool even if it wasn't exact or that detailed as long as the idea comes across. I'm sure there are a lot of people here that would like to see it.

Cheers,
JS

Psyhke
08-11-2003, 05:01 PM
Ryan,

Thanks for posting! I just watched Children of Dune last week. You guys did a great job, I was impressed.

It's great to come here and read some behind the scenes tid-bits from someone who had their hands in the project.

:D

Elmar Moelzer
08-11-2003, 05:20 PM
Hey Ryan!
Great work on that water! I am absolutely amazed.
What machines were rendering 1.5 hours a frame on that? I would have expected it to be a bit longer, especially since it was done to HD- TV- res.
CU
Elmar

RCFX
08-11-2003, 05:33 PM
Our machines varied anywhere from 400 mhz to 1.5 ghz if I remembe correctly. Most were 800s or 1 ghz boxes I think. Criz...if you read this, correct me if I'm wrong. Keep in mind that, though it was a dense scene, I often used larger voxels with fractal break-up, which allowed me to use fewer particles...especially in the bulkier midsection of the flood. I would go back and forth daily between higher particle counts to bigger voxels trying to find a happy medium. The lead emitter, which was spewing out a ton of particles, gave the impression that the whole mass was that dense. In truth, those lead particles had something like a 20-30 frame lifespan and were followed by a much thinner stream with denser voxels. This kept the overall particle count managable.

archiea
08-12-2003, 12:49 AM
Thanks for the reply.....
BTW, in managing volumetric renders, is it possible to also render it at half the rez? especially with smoke, this allowed for reducing the rendering time in some of the shows I worked on. and since it was an element that was to be embellished anyway, the resolution hit wasn't noticable.

In the future, try and see what you can get away with rendering at half the rez and up rezing it in the comp. especially in shake, the scaling tools are very good....

Another possibility is using twixtor as an inbetweener, so you an also save in tempooral resolution. this is limited and introduces its own set of problems....

RCFX
08-12-2003, 12:59 AM
I have done half-res voxel renders in the past and yes, it can be a big help. I held off doing it in CoD since my water spray was supposed to be tiny. In my mind, the NTSC pixel was already bigger than I wanted my drops to be. The larger voxels also had tons of fractal detail. Half res would have eaten away at this and given me an overall softer look. It can be great for distant smoke plumes and whisps of dust, but for trying to creating thousands of water droplets, I'd be real hesitant to go half res.

chriz
08-12-2003, 04:35 PM
Originally posted by RCFX
Our machines varied anywhere from 400 mhz to 1.5 ghz if I remembe correctly. Most were 800s or 1 ghz boxes I think. Criz...if you read this, correct me if I'm wrong.

The LW nodes for CoD ranged from 1-2 GHz, with most in the 1.8GHz range. Voxels are generally fast unless they interpenetrate or (worse) pass the camera plane.

As for rendering half-res voxels; if the alpha channel isn't super-critical (like if you're not cutting through heavily detailed matte objects), then voxels at half res and low AA levels work swell. My girlfriend and I just did a 4K project where several of the voxels were done at quarter-res, often spliced right next to half-res and full-res voxels. We were suprised how well they worked. I wouldn't mess too much with a lower temporal resolutions, though, as even the best motion stretchers often get 'steppy.'

RCFX
08-12-2003, 04:45 PM
Wow...were they really that fast? I know we had a couple of 800's around (I started out on one) and there were a couple of 400s on the stack that I avoided like the plauge. But I didn't know the rest of the stack was that fast. Wow...I guess my scene really was an evil render. Thanks for the info Chriz!

Barred
08-12-2003, 05:10 PM
Thankyou for bothering to reply/starting this thread.

I have only seen the clips from Sigraf yet as CoD has not been shown here in the UK yet (I will be annoyed if I have missed it) and I was gob smacked at the bits I saw.

It is sceenes like thes that prove that there is life in the old horse yet, and I would hope quell the doubters.

Fantastic work guys.