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Selecting Mat/Obj ID's in PS.
show user profile  FX
Whats the optimal way to select your Mat/Obj ID passes in PS ?

I seem to be getting very noisy edges, and whatever method I use I'm getting rough selections particularly on curved edges.

I know there's an option to AA the passes in Vray, hope it's not a dumb question but what AA does that use ?..the scene AA or something else ?

Is there a definitive workflow for this ?


read 668 times
2/23/2015 12:11:52 PM (last edit: 2/23/2015 12:12:46 PM)
show user profile  reeves1984
You wouldn't need to consider the element for AA in that instance because it is would have been considered in the main 'beauty' render

it's a really useful option if for example you wanted to overide all the materials with black, but use multimatte on some objects.
VRay would undersample everything thats black and your multimatte would look shite.

To answer the other/main question, how are you selecting the colour? Compositors will tell you that the only really reliable way to make ID's is using the RGBA channels, and not random colours.
In PS you can then select the channel to make a mask

Simon Reeves - VFX Artist & Blog
twitter <-- I work here

read 649 times
2/23/2015 12:48:04 PM (last edit: 2/23/2015 12:48:04 PM)
show user profile  FX
I've just been bumbling about happily applying random ID's in max, not really applying much thought beyond that.

It's only for this project I've started to notice the AA issues, I can easily fix them manually with paths and and selections, but as usual was wondering if there's something I'm missing.

I've tried every selection method known to man in PS to select the colours, but they all result in some kind of AA/edge issue needing a manual fix.

I'm zooming in to 400% , maybe obsessing a little over the detail, like I say it's easy enough to fix manually but I want the *optimal* workflow, hard to confirm what I'm doing is right with the confusion and contradiction of the internet.

read 641 times
2/23/2015 1:17:13 PM (last edit: 2/23/2015 1:17:13 PM)
show user profile  mike_renouf
Maybe this is of some use?

"ID Element are not anti-aliased

VRayMtlID and VRayObjectID are Integer ID passes and are (correctly) not anti-aliased. Normally when compositing they should be multiplied by a coverage mask to give the correct alpha. Alas I can’t find a Vray coverage element for 3dsmax. But we can create one from the g-buffer using the standard .exr dialog ( but only in V-Ray Adv not V-Ray RT)

Note: Normally I’ll set up simple: Red,Green,and Blue self illuminating materials to do masking rather than ID elements. Because it’s easy, and I get nicer antialiasing."

read 635 times
2/23/2015 1:44:01 PM (last edit: 2/23/2015 1:44:01 PM)
show user profile  FX
Cheers guys, yeah time to learn a better method, I'm giving multi matte a shot,

"Normally I’ll set up simple: Red,Green,and Blue self illuminating materials to do masking rather than ID elements. Because it’s easy, and I get nicer antialiasing"

This sounds interesting, nice link, thx.

I've been a bit lazy up till now, Ctrl - a.... apply random ID's.... render :)

read 632 times
2/23/2015 1:56:19 PM (last edit: 2/23/2015 1:57:49 PM)
show user profile  9krausec
Since I do a lot of post work on a large number of renders I needed a way to incorporate my matte selection into actions. For this reason I Select > Color range for my selections with the "fuzziness" turned up to as far as it can go without having other colors being selected.

Only issue with this that I can tell is if you have many similar colors for your matte pass. Then you start getting selection bleed. Also this doesn't work in 32 bit.

- Portfolio-

read 628 times
2/23/2015 2:19:00 PM (last edit: 2/23/2015 2:19:00 PM)
show user profile  FX
Yeah selection bleeds an arse, and the fuzziness option adds an *unknown* to the workflow.... still experimenting but the cleanest and quickest method I've found so far is using render masks with this script....

read 625 times
2/23/2015 2:55:42 PM (last edit: 2/23/2015 2:56:56 PM)
show user profile  9krausec
I'm sort of surprised there isn't some mathematical plugin that allows you to instead of rendering matte objects out by color do it by numeric assignment. If that makes sense... Probably would be a pain to cross develop for the 3D software as well as the post software.

- Portfolio-

read 617 times
2/23/2015 3:45:30 PM (last edit: 2/23/2015 3:45:30 PM)
show user profile  reeves1984
It's going to be in the format of an image, most practical way to get that info in there per pixel - but think of the colours as numerical, some random green colour = 0.12,0.81,0.15

Simon Reeves - VFX Artist & Blog
twitter <-- I work here

read 605 times
2/23/2015 7:54:01 PM (last edit: 2/23/2015 7:54:01 PM)
show user profile  joelr
Hey FX,

Did you try wirecolor element?
I get great results for PS selection with it


read 599 times
2/23/2015 9:57:20 PM (last edit: 2/23/2015 9:57:20 PM)
show user profile  BishBashRoss
This can be pretty handy.

read 596 times
2/23/2015 10:05:22 PM (last edit: 2/23/2015 10:05:22 PM)
show user profile  FX

yup, I'm trying them all


Thx, trying all the multimatte scripts too.

I'm probably just going back to fixing these manually, still getting jaggies on the curves...

This one's using matte passes as a mask...

this is also using matte passes as a mask on reflection / linear dodge layer ...

jaggy...messy.....more apparent on darker colours, I've got to get this project finished today so can't spend anymore time on it, I'll just tidy it up using paths and selections for now.

read 582 times
2/24/2015 12:03:15 PM (last edit: 2/24/2015 12:03:15 PM)
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