View Full Version : Render Time

04-16-2009, 10:25 AM
I have a guestion re: render time. I have a large scene (> 1mil Polys). Large modeled background with just procedural surfacing. About a dozen "simple skinned" characters and fog...renders fine....Then I add in 8 volumetric spots and about 50-60 transparent refracting bubbles, one bounce of MonteCarlo (with default settings) and three passes of antialiasing :)! Classic Camera.

The radiosity calcs okay. Then the Frame stops rendering at 7%. I gave up (twice) after 14 hours. I get no "out of memory" note. I am aware of the tricks to fake volumetric spots and refraction, but this is just a still and I'd prefer to to this the "real" way.

Machine: 2.6 intel dual core, 4 gigs RAM.

Any help with this issue is appreciated.

04-16-2009, 10:52 AM

Okay, I'll see if I can help a little.

Procedural textures are more CPU intensive.
50-60 refracting bubbles... You've set ray recursion to a low number?
Classic camera... why? Perspective camera is faster at many things.
Fog plus 8 volumetric lights... This is probably your biggest problem.

04-16-2009, 11:31 AM
I lowered ray recursion from 16 to 4. Switched to perspective camera. On a limited region render, that definitely helped render time...we"ll see on a full render tonight! Thanks so much!

The other side of my question, I didn't make clear. The render stops at 7% after a few hours and stays there until I abort (10 hours later). Is this an out of memory issue or something else? Any help there? Thanks.

04-16-2009, 11:46 AM
Something else, I'd wager; the calcs of all that madness through all that... yes, an overwhelmed render engine. Where that one juncture is, no less.

04-16-2009, 12:13 PM
So, I take it there is no easysolution if this won't render. Some bottle neck in my processor that gets "stopped up" and "gives up"?

And I take that faked volumetric lights would give me the most bang for the buck at reducing render complexity? I tried the technique of faking fog with moving textured polygon with motion blur, but it didn't seem the extra calc time for motion blur made it worthwhile. I'd hate to forego the actual refraction calcs with fakes.

Maybe I could stitch together partial renders in Photoshop :0). Or is ther a plugin for that?

04-16-2009, 11:50 PM
Fog plus 8 volumetric lights... This is probably your biggest problem.
I concur! That is a killer. Rendering them separately shouldn't be too difficult.

You didn't mention if you'd turned on 'Interpolated' radiosity, just checking -

04-17-2009, 06:07 AM
You didn't mention if you'd turned on 'Interpolated' radiosity, just checking -

Interpolated on,yes.

It turns out that lower ray recursions was Drano for the processor...50 minute render. I guess not enough experience, but I should have known that one. Thanks everyone.

Guess I can add a few more volumetrics!!