Multiple MultiMatte Elements

[oliverz3d]

On the project I'm currently working on, I felt it to best to consolidate all passes into a multi-layered EXR file. Of course the ObjectID render element is not anti-aliased, and while there are ways to deal with this in post, it's not exactly optimal. Coverage could be used in this instance in conjunction with the ObjectID, but I do not see a way to export that into the EXR when using V-Ray.

So then we move on to the multi-matte element. I'm not keen on the fact that we need to essentially define Object ID's a second time, there should be a more efficient programmed way to deal with this, but I understand the restrictions of these types of the channels. I'm also aware of the wire color alternative, but if this can somehow be streamlined for maximum efficiency in a future version, that would be great.

Now while we can define 3 object ID's per element, multiple multimatte elements are allowed and appear in the V-Ray frame buffer.

Problem is After Effects using the Fnord OpenEXR/ProEXR plugins recognizes only one multimatte element (perhaps because multiples of the multimatte elements are labeled identically rather than numbered?).

So I'm wondering if anyone could confirm if this is an AE problem or one present in other compositors? I have the feeling Nuke can handle it?

Thanks...

[dcullipher]

For organizational purposes you should name each Multimatte pass. Yes the name duplication is a problem in AE but in other apps they will be seen as a long list of names making them hard to use.

One thing I found when using a single EXR is your file size really kills you so I wen tback to separate files. What I mean is if you have 20 passes total they all get stored in the EXR as full float data and it loads all the passes for each shot whether you use them or not. This translates to 30-40M frames, or larger, which in AE is a bear. Also the EXR is stored as a tile based file. AE likes scanline based files (I could have this backwards but same idea) Nuke can deal with the tile based fine an also fusion I believe. AE it just crawls when you have layers embedded.

Another idea for you mattes is use material IDs instead if you are good with organizing your materials per type of object.

Hope some of this helps.

[instinct]

As mentioned in other threads we do post convert EXRs to halffloat scanline 1 zip. This loads a LOT faster in nuke for obvious reasons.

MMREs need to be named unique and this is not only a problem in AE. We do have tools to manage MMREs here inhouse but a simple solution would be to define a predefined set of MMREs, save them in an empty maxfile and merge them into production files as needed.

Regards,
Thorstem

[oliverz3d]

Excellent input, many thanks..

I'm naming my MMRE's for the next render test, glad to see that works.

Yes, I've noticed with AE, at 1080 HD it's rather painful, ideally it would be great to extract the desired passes only at load time, even if that necessitates the creation of a separate file. And using a dozen plus MMRE's isn't going to help matters speed wise wither.

We're working remotely so I find it easier to stick with a single multi-layered EXR, even if worst case scenario, passes need to be extracted into individual files. Defeats the purpose to some extent, but keeps the back and forth sharing more efficient and cleaner. Besides, final comp will be handled in Nuke, not AE.

Thank you for the EXR tips and that's a terrific idea with merging predefined MMRE's in an empty max scene files Thorstem.

Btw, what were you thinking of "Another idea for you mattes is use material IDs instead"?
I was under the impression the MMRE MatID was a toggle option, reading the ID's input into the MMRE as MaterialID's versus ObjectID's?

Thanks,

OZ

[dcullipher]

The multimatte can work in 2 ways, by object ID or material ID. You can either define a separate Object ID for each object in its properties or Define Material IDs and use those. Or both in individual Multimatte elements. r

[oliverz3d]

I got that dcullipher, thanks, but you seemed to imply using material ID's can be more efficient than utilizing object ID's?

Perhaps you're refering to the ability to change material ID's en masse in 2010's material explorer? Autodesk really needs to add an ObjectID column option to the scene manager....

[dcullipher]

Its only better if you organize materials better. Sorry for the confusion
I wish there was a light Lister type Mod for the object IDs. Its a bitch when you forget one object. For an emergency mask I use the rendermask Script. It works great.

[oliverz3d]

Okay. Yeah that would be nice, I've had the same happen to me, very annoying.

In the meantime, being on the Max beta, I'll push for Autodesk to add a lister function for Object ID's in Max 2011.

Thanks for mentioning the rendermask Script, nice find!

[dcullipher]

No worries man. Glad to help.

I love that the new multimatte works on transparent objects. Finally!

[oliverz3d]

Just came across a useful script for seeing all used ID's in a scene, assigning ID's etc.

Not only that, it can automatically create MultiMatte Render Elements based on your ObjectID or Material ID's. You do need to hit the update button to see the used ID's in the scene and when creating Render Elements be sure that the Render Scene window is closed.

Worked perfectly, really nice!

Called VrayEffectsChannelSet, it was just updated last month and is part of a pack that you can find here:

http://www.3d-kstudio.com/readarticl...ectsChannelSet

When you goto customize toolbars after installing, it's actually called Object&MaterialID.

Big thanks to Alex Kramer for this...

[3sgteMKI]

^ Link is broken, any idea if theres a good solution? I'd really like a way to automatically add a/b/c/d/e to multimatte elements.

[dlparisi]

^ Link is broken, any idea if theres a good solution? I'd really like a way to automatically add a/b/c/d/e to multimatte elements.

I just posted a script that does just that...http://www.chaosgroup.com/forums/vbu...nerator-Script

Please give it a go around and let me know how it works (or doesn't for you).