Meeting a crazy deadline (please help!)

[enealefons]

Dearest all,

I bought Octane and 2xGTX580 a week ago and decided to switch from Mental Ray.
Horray! So I ended up in the wonderful situation I am now, of needing to deliver 5 night-shots of the attached lobby, in 5 hours.

I'm cheerful but the time is running and the render is SLOW:
I tried Diffuse Directlighting, but it's too slow and it seems not to resolve well the light coming from the neons at the border, so I switched to Pathtracing.
Now after 20000 samples in more than 1 hour of rendering in Direct Lighting, I still have a very strong noise.

Is it normal in a scene with so many light emitters and glossy surfaces?

Maybe the settings of the blackbody emission could be the key to distribute light better and reduce noise?

I am pretty clueless. By looking at the picture, do you have ANY suggestion for me to tackle the problem? where do I optimize the whole thing?

Thank you so much in advance!

Enea

[enealefons]

trying PMC now... forecast is 1:00 for 10.000 samples... crossing my fingers...

[enealefons]

PMC looks promising... at 2.500 samples I already have a picture with the same level of noise of a 20.000 samples Pathtracing...

Let's hope it will get better soon...

[matej]

Those tiny bright spots, which are reflections (or caustics? / fireflies?) of your overexposed lights, will never get better and look quite ugly. You should probably tone down those lights, which are practically pure white. But now with the tight deadline, it's hard to play with settings and search for alternate solutions...

[enealefons]

Those tiny bright spots, which are reflections (or caustics? / fireflies?) of your overexposed lights, will never get better and look quite ugly. You should probably tone down those lights, which are practically pure white. But now with the tight deadline, it's hard to play with settings and search for alternate solutions...

Indeed...
The spots you see are supposed to be halogen "stars" on the ceiling... it's a client idea and I agree they sould maybe be a bit less bright....
With PMC the noise is slowly getting to an acceptable (and filtrable) level, but the rendertimes simply won't match my needs: I can't afford 2 hours per render, especially at screen resolution...

Plus, I really dislike how the rendering is coming out: I'm so far away from photorealism... I hope I'll be able to catch-up with photoshop.

[remon_v]

If you have your camera response off, and you're not rendering with gamma 2.2 everything looks darker anyways.
I would choose a camera response for now.
Maybe the spherical lights are the problem for the noise.
You also shouldn't touch the 'rayepsilon' settings.

[rappet]

http://render.otoy.com/forum/viewtopic.php?f=6&t=24643
This post has some tips to my questions about fireflies...maybe help for you.
Render in bigger resolution, do some noisereduction and rescale to smaller resolution may help a lot.
Good luck.

[enealefons]

Matej and Remon, thank you for your suggestions and remarks!

I am starting to get a good light response:
I changed all light intensities in order to match the watts and now I'm working with 500 ISO, Exposure 5, Gamma 1, linear camera response.
Unfortunately I seem to be able obtain a good distribution of light only with PMC... with which I'm rendering a mere 640x480 in 1h...

I didn't touch the rayepsilon settings

[enealefons]

http://render.otoy.com/forum/viewtopic.php?f=6&t=24643
This post has some tips to my questions about fireflies...maybe help for you.
Render in bigger resolution, do some noisereduction and rescale to smaller resolution may help a lot.
Good luck.

Thank you!!!

[remon_v]

My standard rayepsilon settings is: 0.0001000
my standard rrprob is: 0.0000
Don't know what the rrprob settings does, but I would leave it at default.
I know the rayepsilon has to do with scene scale if I'm correct.
Maybe set the fstop to 2.0 or 2.8.