which light for a character to calculate?

[jeremybirn]

Could you please explain your question more? Are you asking about which lights need to contribute to a global illumination solution, or which lights are transmitted through subsurface scattering, or some distinction like that?

-jeremy

[mister3d]

Could you please explain your question more? Are you asking about which lights need to contribute to a global illumination solution, or which lights are transmitted through subsurface scattering, or some distinction like that?

-jeremy

Hello Jeremy! I'm pretty happy to see you replying for my questions! :)

Well, I'm seeking for a compromise with global illumination and character anumation. I will need to make approximately 4 minutes of a character animation in environments, up to 5 characters together in a scene.
So as fas as most probably I will need to make lighting rigs for each character, I'm wondering whether key light should be calculated in gi, if I use any kind of fake fill gi.
So I was thinking about ambient oclusion shader in mr, I use 3ds Max 8. But ambient occlusion shader makes not very realistic results, but it's good if you have just ambient lighting like sky, so I thought about hdri for fill light.
But I tested V-ray, and it's very fast. And hdri is fast there too.
Mostly the environments will require soft shadows, so maybe there's a workaround like this:
in mr I can make my own hdri from a scene, and use it in vray as a fill light for characters, plus key and rim lights. How do you think, will it give any speed-up?
Actually, yes, I'm asking which of 3-point light scheme lights need to contribute for gi solution.
I will test V-ray, maybe I can use its gi for characters, I'm not sure, but it's really fast.

[Tamis]

Im no real pro but i am curently producing a small CG shot with a character walking thrue a hall with real life footege and what im thinking of doing is build a Spherecle enviorment of the location and use that to produce collors and light, it isnt realy a hdri but it dose the job as fill light and giving the scene that extra realism then what i do is i look at with direction the most light is comming from like lamps and windows and make spotlights from there with propriat collors for blending il also put some far and near atentuation within the spotlights so light wil increase or degrease when moving past or to a spotlight.

maby this helps you in your question.

[mister3d]

Im no real pro but i am curently producing a small CG shot with a character walking thrue a hall with real life footege and what im thinking of doing is build a Spherecle enviorment of the location and use that to produce collors and light, it isnt realy a hdri but it dose the job as fill light and giving the scene that extra realism then what i do is i look at with direction the most light is comming from like lamps and windows and make spotlights from there with propriat collors for blending il also put some far and near atentuation within the spotlights so light wil increase or degrease when moving past or to a spotlight.

maby this helps you in your question.

But why don't you use a hdri? You will have a limited range with pale lighting. There are some free hdri's on the Net.

[Tamis]

ah i think i gave a bad explenation there.

im shooting a shot with a camera and then im gona put CG in the camera shot.
so using an HDRI of the web wont help me tryng to blend the CG in the footege.

i know an image creates pale lightning but then again its just to bring in the collors of the surounding and im also gona tweak the image more so the lights wil shine more.

[jeremybirn]

First, look carefully into your baking options, to see if you can bake the illumination (including soft shadows and GI if you want it) on the sets. That can save a lot of time.

For the characters, if HDRI is fast enough in your renderer, then that could be a good source of fill light. You might also want regular spot lights you can aim for the key on the characters, and of course if you want rim lights you have to aim those. As long as you have a good key light with real shadows, I'd think that ambient occlusion on a fill light ought to be workable.

In terms of how the characters affect the environments, usually some shadows and occlusion onto the ground are enough. Even if you had very colorful characters, tinting the occlusion from them a little is still faster and simpler than doing full GI for irradience from them onto the set.

In terms of characters bouncing light onto other characters, usually that's so subtle that a little fill light could do it, if it were needed at all, and again full GI on the characters could be overkill.

In terms of using GI for the characters to receive colored bounce light from the environment, only do that if you can get it to happen fast enough. Otherwise aiming some bounce lights up at them is usually the faster route.

-jeremy

[jeremybirn]

ah i think i gave a bad explenation there.

im shooting a shot with a camera and then im gona put CG in the camera shot.
so using an HDRI of the web wont help me tryng to blend the CG in the footege.

i know an image creates pale lightning but then again its just to bring in the collors of the surounding and im also gona tweak the image more so the lights wil shine more.

HDRI spheres aren't really good for the impression of a character moving through different pools of light or in and out of shadows. Of course if the character is reflective at all, then you'd want some kind of environment map made from the hallway anyway, so it's no harm in making one.

For interior match-lighting through a hallway you might try taking a reference shot of a white or gray ball moving through the hallway where the character will be, then light a primitive sphere to match the tones you see on the reference sphere at different points in the hallway. Once the colors and tones hitting the top, bottom, and sides of the sphere match your reference ball, that lighting should match on the character as well.

-jeremy

[Tamis]

thanks for the insights jeremy i wil defenetly try to do it this way.

1 question tho do you know were to get these sorts of refrence balls ? hehe
wel i dont know what you use for it ?

ooh and i just noteced you wrote that book texturing and lichtning or rendering and lightning.
if red your book myself and learned alot of it and would want to know what you updated in your second edition as i might find it intresting to buy.

[mister3d]

Thank you very much for this detailed explanation, Jeremy! That's really helpful! That's explained almost everything to me. :)
To Tamis:
I have both the first and the second editions o Jeremy Birn's "Digital Lighting and Rendering", and I really suggest you the second to buy too! It's as good as it can be, imo! It's divided very logical into 2 sections of lighting environments and architecture and creatures and characters. I received it recently, but I'm just very and very happy with it. It really cleared a lot of my questions, well, it's just perfect! Don't hesitate even a second! :thumbsup: You can visit Jeremy Birn's site to preview :) :http://www.3drender.com/light/index.html

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.