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Too long render times
Posted: 29 August 2012 03:47 AM   [ Ignore ]
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My scene takes too long to render a single image 2 hrs or more
Is there any setteings that i can tweak to decrease render times

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Posted: 29 August 2012 03:58 AM   [ Ignore ]   [ # 1 ]
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  Is this a single image or an animation? If it is to be animation, I have learned the more pieces you have in a scene the longer it will take. And if it is animation, how long is it? I’ve learned a 30 sec clip can take and hour to render, and full 60 sec clip will take two hours, depending on how much is in the scene.Try to minimize how much is in the scene, only use what we will actually see…

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Posted: 29 August 2012 04:05 AM   [ Ignore ]   [ # 2 ]
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omgwtfbbgxy - 29 August 2012 03:47 AM

My scene takes too long to render a single image 2 hrs or more
Is there any setteings that i can tweak to decrease render times

Render times will depend greatly on what is in the scene, the number of figures, is there any transmapped items like hair?  Are you using shader lights like Uberenvironment?  How may lights are in the scene?

What are your machine specs, processor and RAM, Operating System?

Also, can you post a screenshot of your Advanced Render Settings tab showing the values selected?

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Posted: 29 August 2012 06:35 AM   [ Ignore ]   [ # 3 ]
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Its just a single screen
there is 1 uber environment and 4 diff spot lights
yes i have chars with hairs in my scene
My render settings are default settings

I have 8gb ram 560ti graphicsk card
i5 2500k 3.3ghz
64bit OS

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Posted: 29 August 2012 06:53 AM   [ Ignore ]   [ # 4 ]
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Two hours doesn’t sound that long for what you have, several characters, Uber lights etc.  Some people have renders running for many hours, or even days depending on the size and complexity of the image.

What size of a render are you doing, what kind of shadows do you have selected for your lights if any.  Raytraced shadows could also slow things down.

The Shading Rate in the Advanced tab can greatly influence the speed of a render, but I think the default setting is 1.0.  If it is lower than that, say 0.2, then change it.  There are also lots of settings for Uber which can slow the render down a lot.  Try using a Distant Light instead of Uber, just as a test to see if it speeds up significantly.

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Posted: 29 August 2012 07:30 AM   [ Ignore ]   [ # 5 ]
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Learning the ins and outs of Uber environment will help you control render quality and render time.

Same for hair. With hair turning off things like raytracing, occulsion and disabling casting shadows will speed up rendering hair a ton. Usually I leave shadows on, but I tend to disable the first two because you can still have a nice render without them, especially if the scene isn’t a portrait.

I would suggest doing test renders at small resolutions like 300x400 in a render window and watching it progress. You can see where the render holds up.  If you notice it is zipping through most of the image but slows down at the hair, then you know you could optimize how that is rendering. Hair will always be a bit slower than other surfaces, so learning how long is too long comes with practice.

Sometimes it turns out to be something unexpected like glass or a small piece of jewelry that is holding up the render. It’s good to track down what is rendering slowly as it will happen to you in the future. Knowing approximately how long a render will take is very useful. Some hair takes longer to render then other hair as well, so keep that in mind.

I have the same rig as you and the only time I have a two hour render using uber environment is when I render at something like 4000x6000 and the image features wings(with transparencies).

Short of that I keep my renders under 45mins and shoot for 25. Once you learn the settings to tweak, it becomes very easy to apply the logic to other renders.

When using uber environment with a lot of other lights, the quality of uberenvironment doesn’t have to be as high to keep the image quality good. When you use uber environment alone the settings need to be higher to keep the sharp visual. So just as example these two settings will look about the same

uber environment alone
shading rate 8
occlusion samples 128
max error .1

uber environment with other lights
shading rate 32
occlusion sampes 96
max error .2

This could take an hour or so off your render time. If it looks good or not will depend on your scene, so it’s really just giving you an idea of what to work with. The lower the shading rate, the longer the render. The higher the occlusion samples the longer the render. The lower the max render, the longer the render.

All that said there are times when I know I can’t do anything about certain settings, like the transparencies used to make wings, and I deal with the longer render times. I have had one or two 7 hour renders because of prominent wings, hair and foresty type stuff. Sometimes it’s worth it and you let it run overnight. But you should know what you are getting into before pressing the render button for the last time, and you can gauge that by doing test renders.

[edited for clarity and formatting]

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