Invisible wrote:
> nemesis wrote:
>> I want povray to evolve.  Being provocative is a way to do that.
> 
> No - being provocative to the point of trolling is a way to get 
> everybody to completely ignore you. ;-)

eventually, that kind of attitude will lead to everybody ignoring 
povray, except for the geekiest of geeks...

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Invisible <voi### [at] devnull> wrote:
> Does anybody, anywhere, have any details of how the algorithm actually
> works? As in, how is this different to a normal ray tracer?

Yeah. Just search google:

path tracing
monte carlo path tracing
bidirectional path tracing
etc.

Basically it is this simple:

1. You shoot ray to scene and let it bounce randomly as it wants based on
material characteristics.
2. Repeat many times.

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Invisible wrote:
> OOC... Clearly Crysis has some pretty serious graphics. But is it *fun* 
> to play?

dodging the real-time rendering quality discussion by asking about 
something so irrelevant as the game itself or if it is any fun? ;)

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nemesis wrote:

> Sure, you can endlessly tweak the povray scene or settings in other 
> biased renderings to get very photorealistic results.  You may also 
> endlessly tweak the light sources and radiosity/photon mapping settings 
> to get the illumination just right.  You can do nothing at all about 
> aliasing of edges against very bright backdrops.

Wouldn't you still need to tweak light sources to get the scene to look 
"right"

> Or you can just buy top hardware, model, texture and drop accurate 
> lighting in your scene and let an unbiased rendering method handle it 
> overnight.

Top of the line hardware is expensive. Having a renderer that can 
produce a usable image in minutes is not. One more thing to throw in 
(This isn't even raytraced, but scanline rendered) at this point, 
unbiased rendering is not practical for creating any 3D animated film, 
or even 3D special effects. The rendering tools they use in the movies 
produce excellent results, sometimes indistinguishable from the actual 
filmed portions.

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nemesis a écrit :
> Invisible wrote:
>> nemesis wrote:
>>> I want povray to evolve.  Being provocative is a way to do that.
>>
>> No - being provocative to the point of trolling is a way to get 
>> everybody to completely ignore you. ;-)
> 
> eventually, that kind of attitude will lead to everybody ignoring 
> povray, except for the geekiest of geeks...

*And* web buttons designers ;-)

-- 
Vincent

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47bd6ea9$1@news.povray.org...

> I can certainly see the advantage of a "I just throw objects in and it 
> works" approach to lighting. But then, that's more or less how POV-Ray's 
> radiosity feature works. You usually don't have to twiddle the settings 
> all *that* much - it's more a question of how many years you're willing to 
> wait for the result.

Just wondering... Could you show us some of your own experiments with 
radiosity in POV-Ray or is your position just theoretical? Because after 
using (and being in love with) POV-Ray's radiosity since 1996 and hundreds 
of tests and pictures later, that's not really what I've experienced. Even 
when using insane settings, there are situations where you just can't get 
rid of artifacts and other problems and where workarounds (or Photoshop...) 
are necessary to hide them. Unbiased renderers do that naturally and 
traditional high-end renderers have lots of built-in optimisation tricks 
that POV-Ray just doesn't have.

> And that's the kind of worrying part - how many years will you have to 
> wait for the result from an unbiased renderer?

As I said it's now used *** for actual production *** of stills (mostly 
architectural, design and even TV commercials) so apparently that's not such 
a problem, at least for commercial production with access to networks of 
fast machines and render farms. But even on a "normal" hobbyist machine, my 
tests with Maxwell were rather positive, i.e. it was slow, but so was 
radiosity in 1996. My "glasses" picture that's in the "Digital art" article 
in Wikipedia took 500 hours to render. For POVers, speed isn't always an 
issue.

G.

-- 
*****************************
http://www.oyonale.com
*****************************
- Graphic experiments
- POV-Ray, Cinema 4D and Poser computer images
- Posters

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>> I can certainly see the advantage of a "I just throw objects in and it 
>> works" approach to lighting. But then, that's more or less how POV-Ray's 
>> radiosity feature works. You usually don't have to twiddle the settings 
>> all *that* much - it's more a question of how many years you're willing to 
>> wait for the result.
> 
> Just wondering... Could you show us some of your own experiments with 
> radiosity in POV-Ray or is your position just theoretical? Because after 
> using (and being in love with) POV-Ray's radiosity since 1996 and hundreds 
> of tests and pictures later, that's not really what I've experienced.

Well, maybe my scenes aren't complicated enough then. Usually if I just 
insert an empty radiosity{} block, I get a reasonable image. Sometimes I 
have to tweat a few parameters and then it looks good. Occasionally it 
just becomes so absurdly slow that I give up.

But then, as you know, most of my renders are pretty trivial. For 
example, the image attached to the first post in this thread. I have no 
idea how the hell it's possible to model something that complicated. 
Surely something like that must take many months of modelling?

>> And that's the kind of worrying part - how many years will you have to 
>> wait for the result from an unbiased renderer?
> 
> As I said it's now used *** for actual production *** of stills (mostly 
> architectural, design and even TV commercials) so apparently that's not such 
> a problem, at least for commercial production with access to networks of 
> fast machines and render farms.

Heh. Any algorithm can be made fast enough if you throw enough CPU power 
at it. ;-) [Er, well, any linear-time algorithm anyway...]

> But even on a "normal" hobbyist machine, my 
> tests with Maxwell were rather positive, i.e. it was slow, but so was 
> radiosity in 1996.

OK, well that's encouraging then...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Severi Salminen wrote:

> Yeah. Just search google:
> 
> path tracing
> monte carlo path tracing
> bidirectional path tracing
> etc.

None of those are search terms I thought to try...

> Basically it is this simple:
> 
> 1. You shoot ray to scene and let it bounce randomly as it wants based on
> material characteristics.
> 2. Repeat many times.

Right. So trace rays, let them bounce off diffuse surfaces at 
semi-random angles, and gradually total up the results for all rays?

Presumably that won't work with point-lights though? (You'd never hit any!)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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Gilles Tran wrote:
> My "glasses" picture that's in the "Digital art" article 
> in Wikipedia took 500 hours to render.

mama mia!  and it still features a strange little dark spot right in the 
middle of the ground...

but it's a wonderful photorealistic povray render...

perhaps fidos could try that one next to see how it comes along. Andrew, 
go to the "Montecarlo path tracing with MegaPov 1.2.1" thread in p.b.i 
to find out more...

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Invisible wrote:
> Well, maybe my scenes aren't complicated enough then. Usually if I just 
> insert an empty radiosity{} block, I get a reasonable image. Sometimes I 
> have to tweat a few parameters and then it looks good. Occasionally it 
> just becomes so absurdly slow that I give up.

default radiosity settings look hardly any better than just simple flat 
ambient lighting.  If radiosity is not getting your render above 1 hour, 
then it's really not doing much.

> But then, as you know, most of my renders are pretty trivial. For 
> example, the image attached to the first post in this thread. I have no 
> idea how the hell it's possible to model something that complicated. 
> Surely something like that must take many months of modelling?

no, most probably a couple of hours in a visual modelling package like 
Blender or Wings 3D.  Many people actually just reuse premade models and 
just work on composition, texturing and lighting.  The real hard work is 
in the rendering, but this is now mostly automated.  You just say "use a 
bright clear sky at 16:00" or "the lamps should be 160W fluorescent" and 
let it go.

>>> And that's the kind of worrying part - how many years will you have 
>>> to wait for the result from an unbiased renderer?

on quad-cores, fidos has been posting slightly noisy results in the 11 
hour range.  In other more mature ubiased renderers, 10-20 hours on 
powerful hardware already give pretty good results for scenes much more 
complex than just RSOCP...

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