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Question about multiple lights - rendertime

Posted: Wed May 07, 2014 6:16 am
by Christerb
Hello!

I'm trying to create a virtual photostudio in 3ds max, but I am experiencing pretty bad render times.

Are there any key things I am missing out on?

I have 4 graphic cards (2 gtx 690's and two gtx 780tis) for a total of 11900 Cuda cores, so there should be decent computing power available.

My test scene is pretty simple - a room, a white background, 5 octane light sources and a human body/face. (sss skin from Icelaglace)

On path tracing or PMC i barely beat 10-15 mb/s. Is the SSS skin really making everything that much harder to calulate, or did I mess up something when I set it up?

What kernel settings would be suitable in general for a "indoor" enviroment like this to make rendering most efficient? (I mean, are there any settings that cause unnecessary calculations, without improving the final result?)

I'm absolutely a newbie, so any help is good help.

Thx for your time!

Re: Question about multiple lights - rendertime

Posted: Wed May 07, 2014 8:33 am
by Seekerfinder
Hi Chris,
Download a benchmark scene & see what you get. It's in the downloads section - 'simple test scenes'.

Hope that helps.

Best,
Seeker

Re: Question about multiple lights - rendertime

Posted: Thu May 08, 2014 3:38 pm
by Christerb
Here are the results from the benchmark scene:



Direct light: 105 mb/s

Path Tracing: 29,48 mb/s

PMC: 22,25 mb/s

Re: Question about multiple lights - rendertime

Posted: Thu May 08, 2014 3:50 pm
by kavorka
10-15 Ms/s isnt bad at all on a scene like what you are describing.

Is the room fully enclosed?
Did you try to delete the back wall and use an HDRI for lighting?
The skin shader probably slows it down a lot as well.

Re: Question about multiple lights - rendertime

Posted: Thu May 08, 2014 4:31 pm
by lixai
@Christerb if you want to know if the sss is slowing you down, just compare a sss setup with just a diffuse setup, and comapre the difference.
you can try to not have walls around your studio, because the default environement in max is black, so you will still have the control of light just from the octane lights. having the setul inside a room will slow your render times because the light is hiting the walls and it bounces around the scene. so you can have only the curved backgound with no walls at all.
try this and let us know if it works better 8-)

Re: Question about multiple lights - rendertime

Posted: Thu May 08, 2014 5:05 pm
by Christerb
Thanks for the answers!

I removed the walls, and some none visible props and speed increased bigtime.

I also experienced a bit with some hdri lights, and that improved speed even more.

Hm. Consider this a beginners mistake! :oops:

Re: Question about multiple lights - rendertime

Posted: Thu May 08, 2014 7:23 pm
by Seekerfinder
Nothing wrong with your setup. Here is the bench thread if you with to compare:
http://render.otoy.com/forum/viewtopic.php?f=9&t=7144

Welcome to the fold!

Best,
Seeker