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Reducing Render Times

Autor Wątek: Reducing Render Times  (Przeczytany 2233 razy)

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Offline Kevin Healy

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Reducing Render Times
« dnia: 20140708, 07:41:07 »
One of the projects I'm working on this summer is a short animation for our planetarium to be played before each show. It will last 30 seconds or 900 frames. Unfortunately, right now each frame takes 1.5 hours to render 1000 samples to produce a noise-free image. I've reduced the number of light path bounces to 3 and that helped. But 900+ hours of render time is too much.

The scene is simple enough. I have taken a hemisphere and sliced it into 12 equal pieces. I've edited these to make doors that open outward like flower petals. I've keyframed the doors to move in a sequence. Outside these doors I added a sphere to apply a starry sky photograph.

I thought I would bake the diffuse color of the doors using the new 2.71 Cycles. This diffuse texture would be applied as a "shadeless" material using a method described by Jonathan Williamson at:

http://www.youtube.com/watch?v=rfVQSDR1fpA

Is this the right way to go? What else can I try to speed up render times?
- Apply the SubSurf modifier or leave it in the stack?
- Increase light intensity a lot, use fewer Cycles samples, and then use compositing to darken the final images? (Does a composite pass slow things down more than the fewer samples increases it? I want the doors not too bright against the dark starry sky.)
- Other methods you have used?

I was going to attach my .blend file for this project, but it is 49 MB (larger than I can post here on your forum). I can post it to my webpage at home by tomorrow night if you'd like to see it.

It is certainly possible I have a very basic setting wrong and the whole render process is slow for that reason.

Offline smm

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Odp: Reducing Render Times
« Odpowiedź #1 dnia: 20140708, 09:00:03 »
File would be helpful. The scene you are describing doesn't seem to need 1000 samples for a noise free image.

Offline Kevin Healy

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Odp: Reducing Render Times
« Odpowiedź #2 dnia: 20140709, 07:23:20 »
I've posted the .blend file to my college website.

You can download the file at www.mesacc.edu/~kev2077220/public The file is 49 MB.

Any advice you can provide would be great!

Offline smm

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Odp: Reducing Render Times
« Odpowiedź #3 dnia: 20140710, 16:11:13 »
Ok, I've downloaded Your .blend and made some test renders. You can reduce your render time to 25-30% of what you have now just by deleting that skydome and using Environment Texture with Multiple Importance Sample turned on (World settings). I'll post some Images (hope you don't mind).
Rendered at 768x768
Unchanged (skydome and 1024 samples):

Environment Texture (position can be adjusted) and 512 samples:

Difference (original on the right side and with Environment Texture on the left side):

The image is cleaner with 512 and even with 256 samples (256 takes 1 min and 3 sec, original -  3.26).
« Ostatnia zmiana: 20140710, 16:15:42 wysłana przez smm »

 

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