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precalculating vray gi
show user profile  digs
good morning

at work we deal with some large scenes, x-ref'd city size scenes - as photo real as we can get in short amt of time. we have a pretty powerful renderfarm in house that is used, and I'm trying to think of ways to speed up workflow

so like, for an episode, we might render 150 different shots from inside a given city - I'm wondering if we would be able to generate GI once at really hi quality, and re-use it for all 150 shots? I havn't tested it on something this big, and am worried there will be artifacting or problems or something

also, we render bips in place of main characters, so for every shot, the bip moves - would that be an issue?
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10/1/2015 2:43:15 PM (last edit: 10/1/2015 2:43:15 PM)
show user profile  donvella
you can render the gi once for the entire scene and reuse for the cameras - the use camera path option is useful for this.

anything animated will need to be done separately. brute force/light cache is good for animated objects. irradiance map is too difficult for moving items (can be done, its a bit of an over kill method though).

read 598 times
10/1/2015 4:00:31 PM (last edit: 10/1/2015 4:00:31 PM)
show user profile  herfst1
I'm curious about the brute force/light cache method. I've read that, haven't tested it, but whenever I've accidentally done irradiance/brute force I've found it slow as hell, so I just assumed brute force is the slower option. So, basically I'm wrong, right?
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10/1/2015 5:01:56 PM (last edit: 10/1/2015 5:01:56 PM)
show user profile  Coxy
Brute force is usually used for the primary pass, not the secondary.
read 571 times
10/1/2015 9:11:50 PM (last edit: 10/1/2015 9:11:50 PM)
show user profile  digs
sounds like it is a feasible option..

how does gi work in vray exactly? coming from mental ray, my understanding has always been that gi is calculated for the entire scene, then final gather was calculated from the camera per frame - which is where flicker most commonly came from

the shots are used as bg elements, so animation flicker isn't an issue here, i just think we might be wasting some time calculating gi 50 times for 50 cameras that are in the same area, just looking in different directions (we render @ 3 - 7k, depending on the shot)
read 556 times
10/2/2015 5:12:36 AM (last edit: 10/2/2015 5:13:34 AM)
show user profile  donvella
It does from the camera too in vray. But u can also add to the ir map from different angles or use an animated camera and just render 1 frame with camera path selected and use that map. I suggest u calculate the map and use the ir viewer in the tools section of chaos group start menu and see what ur missing. Alternatively you can just test a frame using the map on another camera and see if it looks right.

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10/2/2015 11:42:18 AM (last edit: 10/2/2015 11:42:18 AM)
show user profile  donvella
Also. U can render and save out ur ir map at half res and use that, u wont notice much difference in quality at all. With ur lc use world option it should calculate a little more then what the camera sees to over compensate for similar angles.

Ill give u some exact settinga on monday australian time if that helps

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10/2/2015 11:45:27 AM (last edit: 10/2/2015 11:50:11 AM)
show user profile  digs
ok awesome, thanks vella. Im going to try and do some testing this weekend, im curious to see if we save a decent amount of render time
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10/2/2015 3:54:15 PM (last edit: 10/2/2015 3:54:15 PM)
show user profile  STRAT
James, a most useful tip mate. I've been pre-caching at less than half final render size for some time now with no visible downsides.


(Irrelevant request over :)


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10/2/2015 9:04:05 PM (last edit: 10/2/2015 9:04:05 PM)
show user profile  STRAT
Cheers mate, i owe you one ;)


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10/4/2015 12:43:45 AM (last edit: 10/4/2015 12:43:45 AM)
show user profile  donvella
Being in the UK i thought you would be backing the english?

Thanks for the support! I wish i could share your enthusiasm but i dont follow sport, unless u call whale porn a sport. I dont even own a tv =D

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10/4/2015 11:48:25 AM (last edit: 10/4/2015 11:48:51 AM)
show user profile  STRAT
If i was english i probably would ;)


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10/4/2015 12:33:31 PM (last edit: 10/4/2015 12:33:31 PM)
show user profile  donvella
How your testing go?

read 459 times
10/5/2015 10:05:04 PM (last edit: 10/5/2015 10:05:04 PM)
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