GLOBAL ILLUMINATION DISCUSSION

[Tequila]

I think, the problem are complex materials and reflections. I saw images rendered with GI, that where very complex (high poly tank with many details) and took rendertimes about 30 minutes. But that was without any textures and reflections etc. ... I also played with some settings and textures ... you can tweak GI to a good result and even acceptable rendertimes. Play around or read a book (Ebay is not so expensive) about Mental Ray or a simular rendersystem and your rendertimes will decrease.

[Sir_Render]

Greetings,

I went trough all of the posts and i'm sorry if anyone has allready posted this technique.
What might work for speeding up rendering times in animations is using render to texture as a base for your GI setup and then using a standard lighting setup on top of that, sure you won't get away with everything of course, but I think it will help in a lot of situations.

I'll try to post some examples i'm working on at the moment,

greetz

[tripdragon]

Sorry I could not get through this all, but I am curious, did anyone ever get an answer to the 90 minute render ???? Method, ideas >? Size of the file image ?

And what of Realtime hardware cards ?

[MercatorDesigns]

Kinda funny reading through that, 64bit technology is being developed, new hardware will never come out on consoles first. Got a good laugh... man we were ignorant back in 2003 :P

now we have duel core technology, with 64 bit standard, and up to 2 terrabytes of data storage, and oh dont forget the 8 gb of ram!!

as for Global Illumination especially in VRay, I suggest purchasing the new Gnomon DVD's

Global Illumination: Exteriors by Chris NICHOLS It covers Vray, but im sure you can adapt it to your rendering software.

and

Global Illumination: Interiors by Chris NICHOLS

I havent seen Interiors yet, might have to pick a copy up, but Exteriors is very very very good, though he does studder a little bit :P

[panos]

Hello everyone I will add my bit here...
If any of you is interested on faking with many light sources check this website out.
(it also has amazing animation by the way watch it.)
www.lotsofrobots.com
it has really good scripts and one of them generates hundreds of
spotlights with it and places them on a sphere! its really good.
Brilliant website anyway...

[sneaky_d]

mercator - are the Gnomon DVDs good? was thinking of picking up some of the Analogue onces to improve on my concept/storyboard skills.

[Kage]

I quite like GI, but yeah, it takes too long.

I find placement of standard lights can have as good an effect, yet I'm not too good at the lighting

That Fprime would really improve things though!!!

Thats something thats missing from any 3D program. The ability to see in real time, effects that on a CPU would take hours to render.

To allow you to see small changes without long render times (Something that I hate about 3D programs while working on them)

Thats what next generation of 3D programs need. Shame Fprime doesn't seem to be for Max.

We'll soon see hoefpully though, GPU's rendering complex geometry like the CPU does now, and rendering radiosity, GI in real time. Allowing you to work actually IN the GI environment, and not in a simplified version in REAL TIME

Imagine that? Your render would simply already be there, and you could still see polygons and that, but when you move around a light, you'd see the effects straight away!!!

That'd make working with 3D so much more easily, I tell you.

[Cafecito]

I understand Kit's point of view and think Kit has a very valid remark. I do think that GI is great for rendering one frame... a really detailed high quality scene that is so realistic that you wouldn't be able to determine what's real or not. But for animation, I prefer to go with something simpler and quicker. After all, if you are working for a client you have dead lines to meet... make it quick and make it great. If you are rendering something and you have plenty of time on your hands then go right ahead and use GI. You can get a great result from a fake GI lighting that will render faster or go for the real thing and make it look perfect. Last time I rendered with GI was for a client in Las Vegas. What I did was actually a composite of both GI and fake GI. I rendered the background with GI and the animation with a fake GI, threw it into After Effects and voula! No one could tell the difference. It all depends on your preferences, what you are creating, whom you are working for, and how much time you got.

[ienrdna]

Originally Posted by lockdown2000

I have to agree with Zytrex, in that 3 yrs. computer will be well over 3ghz. I am predicting like at LEAST a 7ghz computer will be like MEDIUM end at that time.
cheers all.

written in 0ct 2002

damn I wish i could live in that future

[praveen3d]

You can't blame GI to have such long calculations times without acutally knowing the technique to calculate the gi.
By just turning this two letter (GI), u r switching on the most complex mathematical algorithms in ur 3d software. The techniques like photon mapping, irradiace mapping, QMC sampling, BSDF, BRDF (Bi-Directional Reflectance Distribution Function, Bi-Directional Scattering Distribution Function)etc. have very complex algorithms based on complex mathematical formulas, etc. the renderer must take in account of every light in the scene,every shadows, every materials, whether they r specular, glossy, nonglossy, transparent, refractive etc and the has to trace every rays from the light or from the camera to the objects till the limit to finally shade each sample pixel. So this can take very long time.
and I think, this is why Calculating gi is very slow.

If ur getting horrible results, u should learn ur renderer well, then u have to tweak the GI settings
Normally, U can use a low quality setting to preview the gi lighting & if the lighting is OK, then switch to the high quality setting for the final render, so the trick is in controlling the GI
If GI is very expensive for u, then there r other techniques like Ambient Occlusion, Radiosity etc to calculate the Final Illumination.
Just blame ur Pentium 4 or AMD 64. 'cause still, even these processing power is not enough to calculate the GI solution in just 10 or 20 seconds for a normal desktop user, I think.

And finally, the antialiasing - (Not a part of GI)- takes time to sample every edges of the scene objects that can also increase the final render time.

[Zytrex]

Wow... my thread is still going!

[DJdude]

i use gi for almost every render. mostly because i only do things like clay renders.

[Tjakalen]

The GI look is definantly a major part of any good looking light setup, it's on the rise in games as well, take The Witcher and Mirror's Edge as clear examples, the later has extremly vivid radiosity going too, ofcourse, non of this is dynamic lighting.

I always fake global illumination/radiosity in a similar way and bake that into a lightmap for my scenes. Simply becasue I find this gives me most bang for render time. I use 3ds Max and to me, as in for my own ego, using high-end renderers and timeconsuming settings ise'nt impressing at myself while i'm doing the art. I realize I can use it to get a better results, but not so much that it justify the time I spend rendering. So I use the good ol' scanline renderer primarly, becasue it's fast, and to me that equals more fun.

Here is an typical exampel of some roof props; render time is ~5 seconds on a AMD Phenom 9950, since all the light (except one dynamic spotlight for the suns direct light + shadows) are contained in a prerendered bitmap.