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stib
07-28-2013, 10:22 PM
When I turn on instancing in my scene I'm getting weird noise everywhere. It's particularly visible in the alpha channel:

without instances:
115926
and with instances
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There's nothing in the background, and the only difference is turning instancing on or off for the object. It's causing massive slowdowns of the render, as is does a lot more adaptive sampling of all the noisy areas. And there's colour shifts as well.

This is on Mac64 Ver 11.5 Build 2519

Lewis
07-29-2013, 12:07 AM
This looks more like you have motion blur turned on at camera settings ?

stib
07-29-2013, 12:39 AM
I have MB on for both of those renders, yes. I'm happy with the MB on the geometry, it's just the noise all over the place that is causing the problem.

Lewis
07-29-2013, 12:57 AM
What's your camera type and AA/As settings (with reconstruction filter) ?

stib
07-29-2013, 01:22 AM
Seems to be a problem with the object I'm making instances of. When I substitute another object it works fine. I'll have to work out what it is about this object that causes it.

bazsa73
07-29-2013, 02:14 AM
Seems to be a problem with the object I'm making instances of. When I substitute another object it works fine. I'll have to work out what it is about this object that causes it.
you can fogbugz it as well, can be a bug

sukardi
07-29-2013, 02:20 AM
I think it is one of those invisible/damaged poly or points in your object. Very difficult to clean up...

stib
07-29-2013, 02:26 AM
No, actually it isn't the object, it's using an image to drive the weights in the instancer, like this:
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If I use an image node this is what happens:
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and if I let it go a bit longer it starts rendering a weird plane right through the object
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I didn't wait for it to finish, you can see it's going to take ages to render each frame, and it's doing a whole lot of adaptive sampling on an area that should be completely empty.
If I take away the image that's attached to the instancer weight input I get this:
115931
Took less than a minute, and no noise. Here's the alpha
115933
I tried using different images, and even 3D procedural nodes, but they all crapped out in various weird ways.

stib
07-29-2013, 02:36 AM
workaround: use a weight map instead of an image map. In modeller I just applied the image via Textured Point to a weight map, and it works fine.
Well that was a(nother) day worth of work down the drain fixing something that should work but doesn't. Thank you again LW.

stib
11-22-2013, 12:17 AM
Hmm.. that worked for a while, and now it's doing it with my weight map as well. Sometimes I wonder why I paid all this money for LW. I wish I'd learned to use Blender all those years ago.

Danner
11-22-2013, 06:23 AM
I've seen this on images that are CMYK instead of RGB.

stib
11-22-2013, 06:39 AM
Had a look, but all the images in the scene are RGB, they're mostly jpegs or targas.

jwiede
11-22-2013, 01:46 PM
Had a look, but all the images in the scene are RGB, they're mostly jpegs or targas.

Perhaps try replacing the JPGs with TIFFs? Historically, JPGs have been known to cause some strange issues/artifacts in LW that disappeared when the file format was changed to TIFF.

dwburman
11-22-2013, 04:58 PM
Plus if it's a TIFF you can set it to grayscale and save on memory used for the image.

mav3rick
12-06-2013, 04:26 AM
i experience same **** now... using image map for weighting and i get noise all over image.... if you switch motion blur from PHOTOREAL MP to CLASSIC it works fine.. i am thinking something is badly wrong with pmblur

also if you turn motion blur slicing in instance panel from 10 to 0 if will render OK

stib
12-08-2013, 10:41 PM
I can replicate it without any weight maps or images or anything. All it takes is for the weight control in the instancer to be changing over time - whether it's simply an envelope, or an image with opacity changing over time or a node network that changes over time. What's more, the severity of the effect is related to how quickly it's changing. And as Mav3rick oints out, it's caused by photoreal MB. I tried turning the time slices off in the instance panel, but got instant crash every time.

here it is with Photoreal MB on
118590
and the same scene using classic MB
118591

here's a test scene for anyone to try out. 118587

stib
12-08-2013, 11:11 PM
fogged: https://fogbugz.newtek.com/default.asp?pg=pgPublicView&sTicket=67403_pi7o6c8a