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Unread postPosted: Mon Jun 16, 2008 6:07 am 
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What's your idea on dealing with the noise ?

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Matthias

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Unread postPosted: Mon Jun 16, 2008 9:45 am 
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Right now we are pretty much a (global illumination) Monte-Carlo path tracer---not real time by any means, as you know. So the answer is lots of rays.

Images tend to clean up acceptably around (the equivalent of) 500 rays/pixel. Shadows and diffuse surfaces (i.e. direct lighting) much, much faster than specular/glossy. One big help (besides the usually sampling stratification and importance sampling, etc.) was avoiding a very improbable event from returning a significant lighting value (dividing by a small PDF blows up the numerator and causes hot pixels that take a ridiculous number of samples to clean up. Peter Shirley's book has a bit about that on pg. 178). Recently adjusted those probabilities, and it helped a lot.

Caustics are still a problem (can take a lot of rays), but I think when we get photon mapping added, that's one of its primary benefits.

Hope that's what you were asking.

Hey, let's see some VRED images!


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Unread postPosted: Mon Jun 16, 2008 10:06 am 
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squeen wrote:
Hey, let's see some VRED images!


Do you think you can handle it :twisted: ?

Matthias

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Unread postPosted: Mon Jun 16, 2008 10:14 am 
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Brombear wrote:
Do you think you can handle it :twisted: ?

Matthias

I need something to shoot for....;)


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Unread postPosted: Mon Jun 16, 2008 10:29 am 
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You asked for it :P . We have much better ones than these, but no permission to publish them yet.

Image

Image

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Last edited by Brombear on Mon Jun 16, 2008 11:12 am, edited 1 time in total.

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Unread postPosted: Mon Jun 16, 2008 10:41 am 
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:evil: Is it really necessary to scale these image soo small these days ? There's little to nothing left that leaves the desire to click on the link :(

Matthias

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Unread postPosted: Mon Jun 16, 2008 10:42 am 
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Brombear wrote:
:evil: Is it really necessary to scale these image soo small these days ? There's little to nothing left that leaves the desire to click on the link :(

Matthias


Yup - we still have modem users on this forum and the pictures were absolutely monstrous.

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Unread postPosted: Mon Jun 16, 2008 10:44 am 
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you could always put a link to them

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Unread postPosted: Mon Jun 16, 2008 10:44 am 
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@Brombear: damn! More...more!

EDIT: Sorry Neko. I can link to the gallery if you wish.


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Unread postPosted: Mon Jun 16, 2008 10:48 am 
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squeen wrote:
EDIT: Sorry Neko. I can link to the gallery if you wish.


No, yours are fine as-is - he was just commenting because I changed his inline images into attachments so they don't force everyone to download them every time the thread is loaded.

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Unread postPosted: Mon Jun 16, 2008 10:49 am 
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naa not these days but I promise more images as soon as we are allowed to.

In the meantime we had to return back the 32core machine. Really a nice screamer (did I say LOUD ?). We got some 6-8 fps on 1megapixel resolutions, scaling efficiency was around 85% (getting a 27 times speedup compared to a single core machine), which is not too bad for 1 week of tuning.

Did you see those raw horsepower figures from the new tesla units from nvidia :shock: :shock:

Matthias

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Unread postPosted: Mon Jun 16, 2008 11:14 am 
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OK, I shouldn't have used PNG files, have replaced them with smaller jpegs (smaller than those rescaled png files), so nobody is hurt ;)

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Unread postPosted: Mon Jun 16, 2008 3:28 pm 
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Wow, those are incredible images Brombear. I wouldn't be able to tell them from real.

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Unread postPosted: Mon Jun 16, 2008 9:51 pm 
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Thanx for the compliments. There are still things to tweak like minor bugs within the model itself and still hundreds of features to implement, but its really a rocking trip with something happening everyday. The next image will be one from a real photographic artist. He made me speechless last week when he told me that now he is only limited by his creative genius :oops: Of course he mentioned some small things that would make life easier for him :)

But now back to squeen and his exploration in space, enough highjacking of this thread

Matthias

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Unread postPosted: Tue Jun 17, 2008 3:12 am 
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Brombear wrote:
But now back to squeen and his exploration in space, enough highjacking of this thread


Please hijack. This thread is about computer graphics.

You've probably heard the saying if it looks like computer graphics, then it's bad computer graphics. Well those shots definitely don't look like computer graphics. In particular, I like the top of the car in the black & white airport image---how the glare from the window shield and roof merge into the single reflected color. (I'm curious, do you ever find yourself looking at real objects now with the same critical eye you examine a rendering and think they sometimes look fake? Maybe its just me...:))

Now I understand you are a commercial outfit, so can't freely give away your secrets, but I'd like to turn your own question back at you. "What's your idea on dealing with the noise?" I don't see any noise in the images you posted, so I'm curious as to why you asked. How many rays/pixel? What kind of render times? Just wondering I'm wondering on how far away I am from professional grade applications.

Also, are you running Windows on the 32p machine?

Do you get 6 fsp with the same image quality you showed? If so, that absolutely incredible. How much is hardware (GL) and to what degree is it ray traced. With all the buzz, it seems as if real-time ray tracing is the new programmable shaders. Your comment about the Telsa is true, however I've heard its been difficult to get the K-d Tree etc. accelerators to run on the GPU because of the SIMD and data base access. Programming CUDA is supposed to have a small cache size (32K) or something like that, and that currently GPU based ray tracers are no faster than multicore CPU. However, NVIDIA did just hire Peter Shirley...

Your (or anyone's) thoughts?


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