extreme hi res ocean render

[anthonyh]

hi,
i`m using a phoenix liquidsim as a default grid for a displaced oceantex ocean with foamtex map. it`s working fine but the issue is i need to render out a large image, 20k pixels so naturally rendering out this big is causing problems with memory usage (i have 32gb and it`s using way more than that.) what`s the best way around this ? is there even a way short of throwing more memory at it ? i`ve tried using a plane with a vraydisplacemod on it as an alternative but while the ocean displaces ok the foam doesn`t seem to work correctly, it just seems to make everything whiter rather than just on the crests. i can at least get the plane/displace method to render at 20k by tweaking down the edge length settings but of course there aren`t any such settings using the sim. (i`ve tried lower wave detail in the oceantex map but no joy)
anyone got any hints for this ?
cheers
anthonyh

[Ivaylo Katev]

the memory overload occurs because phoenix builds the entire mesh in prepas, and for such a resolution it contains huge vertex count.
there are two ways to prevent the crash
- decrease the ocean subdivisions, that unfortunately may decrease the quality and may cause sparks and noise on the horizon.
- use vray displacement on simple plane, however it is much slower, because it builds the geometry on demand, it does not exist in the memory all the time.

[anthonyh]

thanks,
yes i thought the displacement was probably happening all at once, it seemed to make sense. but wow is it greedy though. my swap file rose to 100gb. yipes.
i didn`t realise the ocean subdivisions were for the whole ocean, i seem to remember in older version it controlled the horizon subdivs ? anyway that seems to be the key, it`s at least rendering now without eating all memory known to man. no tearing so far.
thanks
anthonyh
ah yes, the horizon does look a bit low poly . 20k makes it look a bit obvious. time to play with settings.

oh and sorry, should the foam work on the vraydisplace plane ? because it doesn`t seem to with the same settings.?
thanks

[anthonyh]

hmm, spoke too soon. it renders at 5k pixels but when i went up to 20k it rendered a blank screen. nuts. is this a result of lowering the subdivs too much ? don`t think i`ve got the memory to go higher.
thanks
anthony

[Svetlin.Nikolov]

Hey,

You can show the foam texture on the plane if you uncheck the 'Use the original non-displaced vertices' of the Foam tex.

Gotta see if I can get the blank screen with too low subdivs as well...

[anthonyh]

hi, sorry it`s been a while, work!
i was getting blank frames on too high subdivs i think, i suspect due to low memory it got confused ? i could be wrong though.
i was able to get my 20K render to work by dropping ocean subdivs to 0.5 and limiting oceantex detail to 10/11 for a full frame from above and i can have higher settings for a horizon view with about 1/3 of the screen full. to be honest i think with some motion blur it`s more than good enough.
thanks for the tip about using foam on a displaced plane. i`ll try that too.
thanks
anthonyh

[Svetlin.Nikolov]

Ahuuum, with too high subdivs you must have been out of memory and the mesh building canceled itself - we print this in the Phoenix log file, but don't pop a message so that the render will not be halted. If there's a chance you still have the log file from this render and didn't open 3ds max anymore, we could verify this, but most likely it's gone forever

Glad it worked out, please do share if/when possible.

Cheers!

[anthonyh]

yeah, it was about 50 scenes ago. long gone i`d think. not sure i want to risk my ssd on another 100gb swap file hammering !
i`m rendering out a 20k biggun now(about 16-20gb mem use). i`ll do a smaller version to see a bit later. there`s no postfx yet and i`m not revolutionising the fx industry by any means but it looks ok.
could always use pointers in shaders etc. one thing i noticed is a little burnout on the foam but as i said a little motion blur should help.
anthonyh

[Svetlin.Nikolov]

Yup, there are some flickering and fireflies issues here and there that we have to track down...

[anthonyh]

and i think my foam material is a bit bright as well.
waves could be a bit higher, little less foam maybe.

[Ivaylo Katev]

yes, i agree the foam is too bright and overpresent
btw, the final scene of got 6 is using the foam map, you can compare your result with it

[anthonyh]

hopefully it`s on a showreel/breakdown, i`ve only got prime for tv stuff. ah yep it`s on the u-tubes.
was theirs displaced or simulated ? looks like both. theirs is a nicer day though, softer waves so less foam ? not to mention the team of 20 artists working for a month on it !
i think mine needs stronger waves to support the foam although there`s a trade off as displacement doesn`t seem to like too high displaced waves or it might need higher subdiv quality which it can`t have because it`s 20k pixels for a poster. easy enough to choke the levels back a bit if there`s time. we`ll have to do an animated version in HD later so i`ll get another crack at it. nice GOT work, they certainly spend there money on that show. i saw spoilers though, i haven`t got past season 3 or 4 was it ?
anthonyh

[Ivaylo Katev]

for real looking storm waves you can't use only displacement, because they are curled on the crest, the wave force can produce better result, for example this video.

[anthonyh]

really cool. i saw it before so that`s what i started out to try and reproduce but couldn`t work it out, kept getting bounce from the simbox edges(another thread). my settings were obviously way off. i also needed to render a much bigger area of ocean at 20k pixels and time is on the short side. it didn`t seem feasible to use the sim method for this, the cache would also have been enormous ?. also (and this is not a dig) i`d like to see this quality of sim on a usable production size ocean you could maybe fly over. the demos that show this off always have a small ocean square only(not just phoenix either). i don`t think our hardware could handle anything bigger than that anyway with the grid resolution necessary ? i might also be doing it wrong. i presume most would sim the closest point to the camera/action and have displaced water in the background but you`d be limited in camera movement. i got a reasonable blend playing with my liferaft sim. still a lot to learn.