> > Just check out the images group. Fidos already implemented simple but fully
> > working brute force to Pov.
>
> Really? That's interesting. So what's the catch? ;-)

I don't know of any catch. The source is still not available, though. The images
look good to me.

> > So no, There is no need to rewrite the whole
> > program. Brute force might make it actually a lot simpler.
>
> Yes, I see how two algorithms instead of one would be a lot simpler...
> Oh, wait...

Of course I meant that bruteforce might be simpler alone than present mix of
many different special cases which need to be taken care of. Of course having 2
methods is more complex than having just one...

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Does anybody, anywhere, have any details of how the algorithm actually 
works? As in, how is this different to a normal ray tracer?

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

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scott wrote:
>> FWIW, I think it would certainly be interesting to have unbaised 
>> rendering as an option on POV-Ray. But the amount of work required is, 
>> realistically, prohibitive. You'd have to basically rewrite the whole 
>> program. And I don't see that happening any time soon...
> 
> Not just the rendering method, but things like different reflection and 
> lighting models, newer methods of increasing the efficiency of ray 
> tracing (I posted a link in the pov4 group), etc.

OK. I wasn't aware that any existed, but hey.

> Given that most 
> people seem to think SDL is POV's strongest point, why not improve the 
> SDL to be more flexible?

Sounds good to me...

>>> You do realise that the big rock in the Cascades demo is an isosurface?
>>
>> Really? I thought it was just a tellesated triangle mesh based on an 
>> isosurface? (Remember, I haven't actually been able to watch the demo 
>> yet.)
> 
> Well yes, of course, nothing can directly show an isosurface, even POV 
> has to sample the function to generate pixels.  But my point was it 
> shows an isosurface in realtime, in fine detail.

My point is that usually, no matter how closely you look at a POV-Ray 
isosurface, it will always be beautifully smooth. Every NURBS demo I've 
ever seen for a GPU has been horribly tesellated with sharp edges 
everywhere. Sure, if you had several billion polygons, maybe you could 
almost approach what POV-Ray gives you... but presumably that would 
require slightly more than 256 MB of video RAM.

POV-Ray, of course, gets round this problem by using more sophisticated 
mathematical techniques than simply projecting flat polygons onto a 2D 
framebuffer. I've yet to see any GPU attempt this.

>> OOC... Clearly Crysis has some pretty serious graphics. But is it 
>> *fun* to play?
> 
> I only played the demo, and it was in a bit of a rush, seemed pretty 
> similar *gameplay* to FarCry, which isn't a bad thing.  Played fine on 
> my nVidia 7900 card, I think I had low or medium detail and it was above 
> 30fps most of the time.  I think you'd need to play a few levels before 
> any new gameplay became apparent, just IMO.

Mmm, OK. Well my graphics card is only a GeForce 7800 GTX, so I had 
assumed it would be too under-powered to play it at much about 0.02 FPS. 
 From the way people talk about Crysis, I was under the impression that 
you need a four-way SLI rig of 8900GTX GPUs just to make it get out of 
bed... Apparently it's not as bad as that.



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

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Bill Pragnell wrote:
> I've certainly heard people say they thought the effects were rubbish 
> when I thought they were exemplary... the Hulk, for one.

The Hulk character and rendering is quite good.  It's so good in fact 
that it's minor details that will set it apart from a real person.  That 
is, apart from the fact that he's a big green hulking jumping like a 
grasshopper! :D

it's the so called uncanny valley effect.  Read more on wikipedia...

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> Reflections JUST WORK. Refraction JUST WORKS. Etc.

Reflections and refractions don't just work. You see no caustics at all unless
you enable them and tweak settings. You see incorrect shadows if you don't use
the proper keywords/settings. Etc. Many things don't work if you don't enable
them.

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

I have seen so many scenes where you still get radiosity artifacts no matter how
hard you try. I'm not an expert so I might be wrong. And with max settings the
speed difference is not _that_ big after all.

> (OTOH, the fast preview you can get sounds like a useful feature. Ever
> wait 6 hours for a render only to find out that actually it looks lame?
> It's not funny...)

Yeah, since each pass in brute forcer is pretty fast, you get to see something
very quickly. And you can quickly decide if the scene needs more tweaking.

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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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