[itsallgoode9]

Since the new update I've noticed that rendering alpha maps are EXTREMELY slow. I render a scene, using 7 nodes, and have embedded alpha map selected. It says the scene will take around 19hrs to render. If I render the exact same scene with alpha map rendering turned off, it says around 2 hrs. Has anybody else noticed this?

[itsallgoode9]

also, just to note, this happens on every scene i try, not just one. When the render nodes are sending the mxi's back to the main computer, if i have alpha enabled, it transfers the mxi's VERY slowly, if at all.

Not sure if I need to post it as a bug, or if there's just something wonky going on in my computers.

[Mihai]

I think you may be running out of ram and using the harddrive as a scratch disk. The channels are rendering much faster in 2.6.10 but they also take more RAM now when rendering, and space in the MXI. Hopefully this can be improved in the future but the speed gains should be well over 3x as fast now to render alpha channels.

[itsallgoode9]

thanks mihai, i'll take a look and see if that's what is happening. My main machine has 24gigs but my nodes only have 8gigs and the renders are 8000x10000 renders, so that seems very likely to be the case. I didn't think about checking the render usage on my node machines...thanks!

[kami]

I noticed that rendering a file with masks (alpha, shadow, material, object) makes a rendering much slower! don't know if this has to do with the newest version, but for me it is half as fast or even slower than without any masks.

my results:
with masks: SL 10.65, benchmark 282, memory used: 3 GB
without masks: SL 13.82, benchmark 1043, memore used: 1.7 GB
both have run for the same amount of time

[itsallgoode9]

Along this same line...it looks like maxwell render is rendering the full image in the background, even if you have alpha only selected.

Two things make me think this...time to render is nearly identical regardless of if i'm rendering alpha only or if i'm rendering the image only (4hrs...seems WAY too high for an alpha render). Also, in the render that i'm doing alpha only, the preview window shows the full image, not the alpha only. Can somebody let me know if this is functioning as expected or if it's a bug?