Some advice to reduce render time

Hey guys and girls,

I’m trying to render some grass, and it turns out very well in my opinion :slight_smile: but the render time of one frame is about 30 minutes, so, maybe someone could look into my file and check if I can reduce the render time, because I need an animation of 250 frames, and this would take ages to complete, not to mention the continuous CPU load.

there is the .blend file http://www.mediafire.com/?nmfq3b1fllfvn86

and this is one frame

Attachments


The texture images weren’t packed with the file, but I gave it a shot anyway. I’m sorry to say that the strand rendering takes my CPU quite a while as well. I’ll bet you’ve tried these things too, but here are my results from a few different changes:

  1. I cut the render time in half by turning samples down to 50 from 100 and it still looked pretty good. There is a little “grain” in the dark areas, but in an animation that almost disappears if you animate the sampling seed value.

  2. My CPU is only about 2 percent faster on this scene with 64x64 tiles, but your results might be better at a different size.

  3. I rendered 19% faster by changing total Max number of bounces in Light Paths to 3 and Min to 1 (from 8 and 3). This did make the scene look a little darker.

  4. Turning off Cycles experimental CPU hair rendering completely changes the nature of the strands, but switching to GPU wasn’t half bad and cut another 45% off the render time.

  5. Checked the “No Caustics” box and had less than 1% difference in render time.

Do I get some kind of blender head badge for spending 3 hours on this? LOL

I think the “No caustics” only helps with certain scenes, with the light source behind a transparent object? does this apply for translucent also? I will not compete for the blender badge though… scared of long render tests :slight_smile:

Hey, thanks for looking into this, I wish i knew how to pack the textures into the file, but I’m new to all this Blender stuff :slight_smile: I wish I could switch to GPU rendering, but unfortunately my Mac’s video card isn’s supported :confused: I will try to make these changes as you suggested and see if I can improve my render time as well

By animating the sampling seed value you mean to set a keyframe and change it through the entire animation?

Yes, the way I animate the seed value is to keyframe the first frame with a 1 and then keyframe the last frame with whatever frame number it is (250, for example).