OTOY Forums

Hi There

I'm rendering a scene now, pathtracing, about a million polys, one hdri, a fair few glossy materials I guess, some with an image for the specular, bumps maps etc

rendering at 3200 x 2000 pixels, number of refractive / reflective bounces set to 4

on a GTX 470, 1248 RAM

admittedly on an old overclocker vista (!) machine, 8 gb ram (DDR2!)

but it's saying 11 hours? Target samples level set to 12000

Is this about right do you think? just that I noticed other images on the forum being rendered in a under an hour or so..


many thanks!

sdwhitton wrote:Hi There
I'm rendering a scene now, pathtracing, about a million polys, one hdri, a fair few glossy materials I guess, some with an image for the specular, bumps maps etc
rendering at 3200 x 2000 pixels, number of refractive / reflective bounces set to 4
on a GTX 470, 1248 RAM
admittedly on an old overclocker vista (!) machine, 8 gb ram (DDR2!)
but it's saying 11 hours? Target samples level set to 12000
Is this about right do you think? just that I noticed other images on the forum being rendered in a under an hour or so..

many thanks!

this depends on ... just everything my personal "record" for 12000s/pix (3840x2560) was over 80hrs on a gtx 570 (about the same performance as your 470); in fact i let it go on for 440hrs to full 64ks/pix, just to test if octane/the pc is able to constantly render for a long time.

btw, as the render time -of course- depends on the rendered resolution, the ms/sec count is easier to compare. my scenes (medium complex usually sunlit interiors) typically run at 1-2ms/sec on a single gtx 570...

ps: to question is, if you really need 12ks/pix for an acceptable image. again depending on the scene (and some render kernel optimization), a value between 2k and 6k might be already enough; what of course results in a substantial render time cut...

ah ok - thanks for your reply!

Yes, I'll see if the sample level could be lower, and yes it's around 1.7 mSec thingys

what are the big hitters in render times?

I could optimise the geometry, or do I concentrate on the materials? less glossy ones, no glass etc

sdwhitton wrote:ah ok - thanks for your reply!

Yes, I'll see if the sample level could be lower, and yes it's around 1.7 mSec thingys

what are the big hitters in render times?

I could optimise the geometry, or do I concentrate on the materials? less glossy ones, no glass etc

well, a trick i have read of (but never done) is to render an interior scene without the ceiling - this will of course only work in some cases. apart from simplifying geometry - if you do interiors lit by hdri enviroment or sun - the use of portals should help, and also to render windows without glass (if possible). if there are additional (inside) emitters, the sample_rate parameter can help to reduce noise (and thus lower render time). also playing with some render kernel parameters might help in some cases (like rrprob). rendering closeups from a bigger scene, it'll be a good idea to take everything out, that doesn't add to the shot.

from my experience, there are no real "big hitters". the more complex a scene gets, the slower it renders; but for me render times are only 2nd or 3rd priority, so there might be still better tips...

OK - thanks again - you might have to explain both the rrprob setting, and portals to me...!

here's the render btw..

this is how it's turned out in the end, well nearly, need to add some glass, maybe over-expose the exterior, and make the sofa look less 'greasy'...

just switched back to Ambient Occlusion, with a sun...

see what you think,

cheers

Steve

Hi,

Radiance made a tutorial about portals in our resources and sharing forum: http://refractivesoftware.com/forum/vie ... =21&t=7210.

The rrprob (Russian roulette probability in full) setting determines how much time the renderer spends on calculating light that reflects a lot of times in your scene between leaving the light source and arriving at the camera. A low setting will speed up the renderer, but can introduce more noise in scenes where light tends to reflect around a lot of times (for example between the walls of an interior). The value of 0 is special, it means the renderer chooses a value automatically from the reflectivity of the surfaces in the scene. This should work well in most scenes.

--
Roeland