nemesis wrote:
> Jim Henderson wrote:
>> On Wed, 20 Feb 2008 16:44:59 -0300, nemesis wrote:
>>> like I said, photorealism is not a matter of opinion.
>>
>> Sure it is.  It all depends on one's perception of the image.  You 
>> might look at an image and say "gee, that looks really 
>> photorealistic", and I might respond "are you on drugs?  Look at that 
>> shadow, that's clearly not right".  You might disagree about that 
>> particular shadow (whatever it is).
> 
> if I saw at a sharp shadow and said it was photorealistic, I'd sure be 
> on drugs. ;)

Any shadow viewed from sufficient distance will appear razor sharp. 
Using sharp shadows for large-scale objects and scenes can be completely 
photorealistic.

>> Have you ever been to a movie with someone who thinks the CG effects 
>> are outstanding and "the most realistic effects they'd ever seen", 
>> only to tell them that they were crap effects?

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

Post a reply to this message

Warp wrote:
> nemesis <nam### [at] nospamgmailcom> wrote:
>>>   POV-Ray is simply a great tool to create "3D'ish" images like those.
>>> It's easy and fast.
> 
>> so, pov-ray will end up its days as a 3D button design tool?  Are 
>> pov-ray users ok with that evolutionary idea?
> 
>   Why are you trolling?

I'm making justice to my nickname.  I want povray to evolve.  Being 
provocative is a way to do that.  You may call me names, I don't care.

Post a reply to this message

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.
> 
> 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.

I find that most of my tweaking in POV is for 'artistic' reasons - 
making sure shadows don't line up with edges, or that the light is in 
the right place to make the objects look right/good, or that objects are 
placed and textured naturally. Only occasionally do I find myself 
tweaking for image quality.

Post a reply to this message

scott wrote:
>> How about, say, volumetric fog? ;-)
>>
>> I have yet to see any GPU of any description get that right...
> 
> A couple of papers show how to do realistic physics-based smoke/cloud 
> true volumetric effects (not just static fog):
> 
> http://developer.download.nvidia.com/presentations/2007/gdc/RealTimeFluids.pdf 
> 
> http://www.markmark.net/dissertation/harrisDissertation.pdf
> 
> Also real-time volumetric lighting is no problem, in fact Crysis uses it 
> and I'm sure there's an nVidia demo kicking about somewhere.

All I know is that every time I play HalfLife 2 (hailed for it's 
ground-breaking graphics), I'm struck by how cheese and lame all the fog 
effects look.

Crysis? Isn't that that game that requires a small render farm to play? ;-)

>> For that matter, I've yet to see any GPU do physically correct 
>> reflections [although surely it can't be *that* hard?],
> 
> The reason there is no effort put into doing this is because doing the 
> reflection/environment map method is good enough.

Probably.

>> nor global illumination that isn't pre-computed [and hence won't 
>> change when objects move around].
> 
> http://realtimeradiosity.com/demos/
> 
> Real time ambient is done in the "Cascades" demo from nVidia.  Each 
> voxel on the surface traces out (32 IIRC) rays to work out the GI at 
> that point.  OK so it's not perfect (other geometry doesn't affect it) 
> but it's certainly better than no GI.

Cascades sounds interesting. I'd certainly like to watch it. However, it 
requires a more expensive GPU and a more expensive OS before it will 
even consider running, so that's kind of the end of that.

> What you have to bear in mind with all these things, is that they have 
> to be designed to work when a frame takes 15 ms to render.  If reducing 
> the accuracy by 10% speeds up rendering by 50%, the speed-up option is 
> taken. Always.

Yes. And that is why POV-Ray can do things that a GPU can't. POV-Ray 
isn't *trying* to be real-time. ;-)

I could add things like isosurfaces to the list. (Have you ever seen a 
game where the water *actually ripples* rather than just surface normal 
tricks?) The point is, POV-Ray has vastly more time to spare, so of 
*course* it can do a better job than any GPU can. Hardly surprising, really.

Just don't try to tell me a GPU can do everything POV-Ray can. ;-)

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

Post a reply to this message

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. ;-)

> You may call me names, I don't care.

Oh the irony...

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

Post a reply to this message

Warp wrote:
>   Btw, does unbiased rendering support volumetric lighting? I can't find
> any example image in this site nor int the indigo gallery.
> 

I'm guessing they're waiting for 16-cores to become a reality before 
supporting it. :)

Post a reply to this message

> Cascades sounds interesting. I'd certainly like to watch it. However, it 
> requires a more expensive GPU and a more expensive OS before it will even 
> consider running, so that's kind of the end of that.

You can watch it on YouTube, you might even be able to find a higher 
resolution version somewhere on the net.

http://youtube.com/watch?v=_tDK2hfxiw0

> Yes. And that is why POV-Ray can do things that a GPU can't. POV-Ray isn't 
> *trying* to be real-time. ;-)

So POV should strive to use more recent algorithms then, not just stick with 
ones that were around 20 year ago.

> I could add things like isosurfaces to the list.

You do realise that the big rock in the Cascades demo is an isosurface?

> (Have you ever seen a game where the water *actually ripples* rather than 
> just surface normal tricks?)

Yes, Crysis for one, plus there's some flight sim which is regularly cited 
in papers about this.  The method used is "vertex texture lookup", whereby 
the position of a vertex can be modified by a texture.  It is available from 
Vertex Shader 3 onwards (ie all cards less than a year or two old).  This 
means a heightfield can essentially be rendered on the GPU with little or no 
effort from the CPU.  If you're doing your water simulation on the GPU 
anyway, this saves a huge amount of bandwidth between the CPU and GPU.

> Just don't try to tell me a GPU can do everything POV-Ray can. ;-)

I'm not, I'm just saying that it can do *most* of what POV can, in a 
fraction of the time.  ANd when people do start to use POV for animations, 
they chop out all the graphical goodies anyway to make it render in less 
than a year...

Post a reply to this message

scott wrote:
>> Cascades sounds interesting. I'd certainly like to watch it. However, 
>> it requires a more expensive GPU and a more expensive OS before it 
>> will even consider running, so that's kind of the end of that.
> 
> You can watch it on YouTube, you might even be able to find a higher 
> resolution version somewhere on the net.
> 
> http://youtube.com/watch?v=_tDK2hfxiw0

Mmm, OK. Well obviously I can't do that from work, but when I get home 
tonight...

>> Yes. And that is why POV-Ray can do things that a GPU can't. POV-Ray 
>> isn't *trying* to be real-time. ;-)
> 
> So POV should strive to use more recent algorithms then, not just stick 
> with ones that were around 20 year ago.

Netwon's laws of motion have been around for a tad longer than 20 years, 
and people still use 'em. ;-)

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...

>> I could add things like isosurfaces to the list.
> 
> 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.)

>> (Have you ever seen a game where the water *actually ripples* rather 
>> than just surface normal tricks?)
> 
> Yes, Crysis for one, plus there's some flight sim which is regularly 
> cited in papers about this.

...starting to see why Crysis is so hard to run... ;-)

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

>> Just don't try to tell me a GPU can do everything POV-Ray can. ;-)
> 
> I'm not, I'm just saying that it can do *most* of what POV can, in a 
> fraction of the time.

Well OK then. That I can live with...

> And when people do start to use POV for 
> animations, they chop out all the graphical goodies anyway to make it 
> render in less than a year...

LOL! Every pover knows it's true... ;-)

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

Post a reply to this message

> 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...

How wrong you are :)

Just check out the images group. Fidos already implemented simple but fully
working brute force to Pov. So no, There is no need to rewrite the whole
program. Brute force might make it actually a lot simpler.

Post a reply to this message

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

>> 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 (you'll see in the demo when you 
watch it).

> 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.

Post a reply to this message