Opinion: Biggest Rendering Time Drain

# 1 23-01-2005 , 02:49 AM

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Join Date: Aug 2004

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For rendering -- I hear a lot about Alias telling people to watch which shader they use, etc. for optimization. And I'm wondering -- what's the biggest time-drain?

Besides hardware particles (running a GeForce card) I'd guess that 2d motion blur sucks the most time out, but raytracing I'd assume would be pretty close.

I'm expecting a little deviation between answers -- but I'm still a bit curious... because I've been getting frames done with dynamic lighting, raytracing, ~50 shaders and have been getting only 2-5minute render times with 8-20x AA... I hear horror stories of 1-2 day renders -- so I know it can get a lot worse... but how?

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# 2 31-01-2005 , 07:16 PM

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Location: Utah, USA

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Hey, phopojijo,
Ever try the frozen particle solution I gave you?

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# 3 01-02-2005 , 06:38 PM

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Location: London

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Use mental ray, the motion blur is alot better and you just need to set up the bsp settings if your using motoin blur (lower bsp size maybe). that will help, use the diagnosis tool under mental ray globals to tweak the bsp.

Tweak the antialias contrast tollerences and filters so you get nice edges in a short amount of time, and only use production quality sample levels when your at final render.

In terms of ray tracing make sure you dont have the trace depth too high than you need, that can realllly slow things down.

Things like Depth of field can slow down render time alot.

hope that helps

FX supervisor - double negative

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# 4 03-02-2005 , 06:27 PM

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Nah -- I was just asking if anyone knew why my renders popped out such a large margin faster than most high-end computers popped out with fairly decent results. Came to me a while ago that most high end computers run radiosity solutions, which when combined with raytracing (like Rhino 3d/Flamingo does --) can take days to properly render.

Before I thought of radiosity, I knew
1) My computer was DEFINITELY slower than Pixar's
2) My render times were in the minutes, not hours, with raytracing and blur on
3) I'm running a GeForce
4) My renders were not all that much worse than some videos
5) I didn't optimize a thing, and lastly
6) The polycounts of my frame are actually quite high, considering.

So something just wasn't adding up -- most likely Radiosity is the missing variable -- that or Pixar Renderman is slow as heck.

(Thanks for the help, but I wasn't actually complaining about my render times -- I was wondering why the horror stories, on better computers, were so so much longer.)

And I didn't get a chance to try your particles solution yet -- been bogged down with a major essay in one of my classes.

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# 5 04-02-2005 , 02:23 AM

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Don't forget that pixar renders out each frame at HUGE resolutions. Plus i used to find when using something like a GI_Joe lighting, which adds about.. 120 lights? ( im not sure on that user added image