Global Illumination and geometry-lights

[squidinc]

yikes, that was a long time ago, er.. I think I used the default settings, I remember it took F@&king ages to render :surprised , lol it was pretty much my first and last radiosity render, I'll have a look if I've still got the file somewhere :)


edit: that render did have some postwork on it as well in photoshop to change the colours a little

[ThirdEye]

Yep, it was ages ago, but i perfectly remember those times... ;) Thank you very much Squid. :)

[AdamT]

You have to use really high stochastic samples when you are using emissive materials--and that applies to HDRI as well.

[squidinc]

this HDRI stuff is pretty cool :)

http://www.m1k3.com/cgremote/hdri01.jpg

[ThirdEye]

WOW! Post it in your Gallery thread too. A couple advices: avoid using planes with GI, it's better if you use a floor object, you'll need lower GI settings. I usually use a floor object and i fade it out with a circular gradient in the alpha channel. 2nd advice: use custom higher gi settings in the compositing tag of the floor object, the shadow will be nicer ;)

[ThirdEye]

Originally posted by AdamT
You have to use really high stochastic samples when you are using emissive materials--and that applies to HDRI as well.

Sadly you're right Adam, it's such a pain to render a pic with 200 samples in stochastic mode. :hmm:

[AdamT]

Don't use stochastic mode! Use adaptive radiosity but with higher samples (or higher quality--same thing).

[ThirdEye]

No it's not the same thing. Samples aren't related to accuracy, only min/max res are. Btw i won't use Stochastic Mode, too slow and too noisy. ;)

[Per-Anders]

actually samples are, think of them as attenuation between min and max, like working with a gradient, only this time you're working with min/max settings.

[ThirdEye]

finalRender tutorials don't agree with you two. According to them "accuracy" balances the "min/max res" settings and the "stochastic samples" number is the number of samples that each "photon" emits. So in a certain way you're right, the higher is the "accuracy" the higher will be the number of samples but what i meant is that "accuracy" regulates also min/max res, "stochastic samples" doesn't. :)

[Per-Anders]

ah, yes you're totally right, my bad.

[AdamT]

I'm not so sure. How exactly does the accuracy setting "balance" the Min/Max setting? It appears to me that it only acts as sort of a multiplier on the number of samples.

[ThirdEye]

Yep: the min/max res regulate the amount of white dots in normal/difficult areas. It means that the dots number in flat areas (like a plane) will be driven by the min res value, the dots number in corners (or where 2 surfaces meet each other) will be driven by the max res value. finalRender tutorials give us an advice: min res should be AT LEAST 1/10 of the max res. (i usually use 3-25). Actually min/max proportion is tweaked by accuracy. In fact accuracy doesn't change the min/max res proportion, it only increases the number of white dotsyou see on prepass. Each dot will emit a certain number of samples (stochastic samples), as explained in the Advanced Render manual. :wavey:

[MJV]

C4D's radiosity explained in detail: http://www.mvpny.com/RadTutMV/RadiosityTut1MV.html

[AdamT]

Originally posted by ThirdEye_01
In fact accuracy doesn't change the min/max res proportion, it only increases the number of white dotsyou see on prepass. Each dot will emit a certain number of samples (stochastic samples), as explained in the Advanced Render manual. :wavey:
Or in other words, both accuracy and samples regulate the number of samples--which I believe is what I said above. Not coincidentally--since I picked it up there--MV's tutorial says the same thing.

[ThirdEye]

Originally posted by ThirdEye_01
So in a certain way you're right, the higher is the "accuracy" the higher will be the number of samples but what i meant is that "accuracy" regulates also min/max res, "stochastic samples" doesn't. :)

[AdamT]

Not trying to be difficult--just trying to make sure I understand. But, how does accuracy "regulate" Min/Max? In other words, increasing the accuracy does what--lower the Min/Max ratio, raise the ratio, perform some kind of algorithm, and to what effect? Literally speaking, stochastic samples also "regulates" Min/Max, in that raising your samples will give you finer-grain samples per Min and Max number.

[ThirdEye]

Look at this pic. I took a pic from suurland.com, it has a RIGHT disposition of the white dots (in finalRender they're green). In this pic i show which areas are influenced by min/max res parameters and i underline the concept of stochastic samples. To be more clear i assume the "stochastic samples" parameter is set to 3 so it means each white (green) dot emits 3 samples. The Accuracy setting imo acts as a white (green) dots multiplier. I hope it helps. :)

http://digilander.libero.it/ThirdEye_01/fix/example.jpg

[kiwi]

I was just going to mention your brilliant tute MV :thumbsup:


Just curious how long did the tute take to finish?,reason I ask is because I seem to remember a number of those images took an hour or more to render,and there are lots of them :)


Stu.

[ThirdEye]

Originally posted by squidinc
yikes, that was a long time ago, er.. I think I used the default settings, I remember it took F@&king ages to render :surprised , lol it was pretty much my first and last radiosity render, I'll have a look if I've still got the file somewhere :)


edit: that render did have some postwork on it as well in photoshop to change the colours a little


if you succeed to find that file i'll be the happiest person in the world, rendertimes are killing me :cry:

[MJV]

Originally posted by kiwi
I was just going to mention your brilliant tute MV :thumbsup:


Just curious how long did the tute take to finish?,reason I ask is because I seem to remember a number of those images took an hour or more to render,and there are lots of them :)


Stu.

Thanks kiwi. :beer: I don't remember how many days I worked on it. The main time consumer was composing the web pages in Adobe Golive. I made the tutorial in return for some software that Maxon gave me, but after all when I offered it to Maxon they didn't want it. I doubt I'll be doing more tutorials any time soon, but I'm glad you got something out of this one.

[kiwi]

I know lots of people who got/do get a great deal from it all the time MV :thumbsup:


Stu.

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