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View Full Version : Confirm a bug gents?



toby
05-29-2009, 03:00 AM
I get render segment artifacts/banding when I render radiosity and photoreal motion blur with multi-threading. Setting threads to 2 results in top and bottom halves of the frame rendering slightly different, as if they have different radiosity solutions or something. More threads, more bands as you'd expect. No problems with 1 thread, or when switched to classic motion blur, or with cache on.
9.6UB, 2x2 G5, OS10.4.11
Wondering if it happens in 10.5 / intel

rsfd
05-29-2009, 03:32 AM
hi,

never observed such problems under 10.5 on a MacPro.
Will post a screenshot of your scene asap.
(And I'll try to test it on my G5/10.4.11 sometime the next days)

3dworks
05-29-2009, 03:39 AM
confirmed on mac and even under win xp64, see rendering with 8 core nehalem mac below.

-> setting radiosity to 'cached' with animation fixes it - or setting radiosity to not interpolated - rendering of course will take much longer in this case.

cheers

markus

3dworks
05-29-2009, 03:49 AM
btw. try to set blur length of MB to somewhat between 300% and 600% to get a nice blur effect in your scene!

rsfd
05-29-2009, 04:07 AM
ok, confirmed on MacPro.
3dworks has same solution *and* was faster :D

toby
05-29-2009, 01:18 PM
Yea I know the solutions, it's in my first post - and my animation needs to look like it's not motion blurred. Just wanted to confirm a real bug before submitting it.

I'm motion blurring to avoid the flickering without the anim cache, which doesn't work with deforming geo.

toby
05-29-2009, 03:51 PM
Submitted, thanks dudes.

JonW
06-03-2009, 07:15 PM
Happening on E5450, XP64

toby
06-03-2009, 07:28 PM
Thanks for testing. If you submit a bug too it'll get higher priority.

Chuck
06-05-2009, 02:40 PM
I get render segment artifacts/banding when I render radiosity and photoreal motion blur with multi-threading. Setting threads to 2 results in top and bottom halves of the frame rendering slightly different, as if they have different radiosity solutions or something. More threads, more bands as you'd expect. No problems with 1 thread, or when switched to classic motion blur, or with cache on.
9.6UB, 2x2 G5, OS10.4.11
Wondering if it happens in 10.5 / intel

You're looking at the classic use case that led to developing radiosity caching. Formerly, to have multiple processors you would have had to have multiple systems and the problem would have exhibited between frames, resulting in flashing. With multi-processor CPUs you can see it in strips of a single frame, unless you turn on cache radiosity, or turn off interpolation. This isn't a bug, this is how these features work to give you a clean render within frame and between frames when using radiosity.

If you do choose to submit a bug report, though, it might certainly be worthwhile having a new look at the issue, since multi-processor/multi-threaded systems are now becoming the norm. Maybe cache just needs to engage automatically on a multi-processor system if the user sets other options in a way that requires caching to get a clean, consistent render.

Chuck
06-05-2009, 02:47 PM
I'm motion blurring to avoid the flickering without the anim cache, which doesn't work with deforming geo.

Again, we will look into the report, but I don't think we can make the Photoreal motion blur feature substitute for anim cache for you. And until we can improve caching to accommodate deforming geometry, the notion I suggested above wouldn't help your situation either.

toby
06-05-2009, 03:21 PM
That makes sense, thanks for looking into it.