Material ID - what is it?

[Bosseye]

Probably a stupid question, but can someone explain a little more about the Material ID pass? I've tried running one and it shades all surfaces in a different primary colour but I'm not sure what I'm supposed to do with this.

I have searched the various help files but either theres nothing there or I'm being thick.

Thanks

[Zom-B]

It is for post production. with The Mat ID pass you have a selection (using lasso tool in PS) for each material in the scene, and can quickly adapt areas to your needs. Brighten up, denoise or shift color etc.
There are also extra Plugins that help working with theses passes for After Effects etc.

[Bosseye]

Ahhh, I see, thanks. That makes sense

[Zom-B]

Ahhh, I see, thanks. That makes sense

I have to admit that I didn't knew about MatID until Indigo introduced it
Now a MatID pass is always a essential part of my workflow, but I still look forward to a better color distribution...

[Bosseye]

Its a great feature (now that I know what it is...). I've been using it this morning with the lassoo tool in PS to lighten and de-noise certain materials without affecting the whole.

[kklors]

I use MattIDs excessivly, although I kinda miss the feature to assign own colors, or even better having an ObjectID pass ontop.

Usually using it with Color Range selection in PS. Before I babble something without proving it I can't confirm yet what image formats under what condition cause it, but you can have premult real quick with textures containing an alpha channel, which leads to premult in the MatID pass as well causing an outline when you select certain objects using it.

Can post an update somewhen after the weekend, if someone else is interested.

[Zom-B]

Fell free to push this thread here: http://www.indigorenderer.com/forum/vie ... =5&t=12289

the automated color choice of Indigo is sometimes suboptimal, like in this example:

Before I babble something without proving it I can't confirm yet what image formats under what condition cause it, but you can have premult real quick with textures containing an alpha channel, which leads to premult in the MatID pass as well causing an outline when you select certain objects using it.

Sounds like you do alpha rendering with your MatID pass.
Atm Alpha renderings in Indigo always ends up with some degree of transparency in the image, the higher the SuperSampling the harder it gets to "fill up", radial sampling also helps a tiny bit here... I hope for some fix for that issue, maybe with more Render channels sometime in Indigo 4.x

[kklors]

Ah thanks, didn't know that.

In my particular case the effect is not consitant, so it has to be one of the many ways of saving textures 'wrong'.
Just have never taken the time to pinpoint which one of them is premultiplied. The thinner outline can be removed relatively easy in comp, but once you get the thicker one, things might get tricky depending on the setup or using DOF etc.

Also C4D's normalizing textures with sRGB for 2.2 Gamma/Linear Workflow doesn't make things better. Really should take a look into that stuff soon.

[StompinTom]

ObjectID pass would be stellar, to get black and white maps of individual objects or groups.

+1