render layer masks

[WhyGee]

Hi,
A friend using Octane on Cinema4D is able to output render layer masks as single masks for each object ID. In his Render Settings he has the option of selecting which render layer mask Id to output, something that I can't find in Houdini's plugin. In Houdini it can spit out colored masks but correct me if I'm wrong, there is no clean way to key them out if they are not single channel masks? Also the color masks change colors if during the animation one of the object's visibility flag is keyed.

Attached are Cinema's settings if you can advise on how to get the same result in Houdini.

Thanks alot
WhyGee

[RobSteady]

+1 for 3ds Max

[juanjgon]

I think that I don't understand this feature. In Houdini you can save the render layer mask for each layer while it is being rendered, one file (or .exr layer) for each render layer ... do you want to disable the rendering of the render layer masks of some of the layers, or do you want to combine some of the render layer mask files in only one?

I think that in C4D what you are doing is disabling some of the render layers masks, to get less files or remove this layer from some .exr multilayer files.

-Juanjo

[WhyGee]

I hope I'm not mistaken but in Houdini, in the Octane ROP node there is a "render object layers" option which forces Octane to re-render each render layer separately, increasing render times significantly. The screencaps from Cinema show a different workflow option where "render object layers" is not used but the "render layer masks" tab renders a single "complete beauty" and then spits out only the individual masks for each layer ID which is quick and limited by the Max Samples parameter. In Cinema there is also a "render layer masks" toggle which is the equivalent to Houdini's and generates a color based mask but they also have another tab which you can see in the previously attached screenshots that when enabled, creates clean masks quickly for each layer Id without re-rendering the beauty.
I'll try to involve the Cinema guy in this post if I'm not being clear. Let me know please.

Thanks alot!

Yaniv

[juanjgon]

So what you say is that the C4D plugin can render the beauty passes (all, without re-render each layer, like if the render layers feature was disabled) and later, after finish the render, it can render in a second pass only the render layers masks quickly without re-render all the other passes, right?

-Juanjo

[WhyGee]

Yes, I'll get the Cinema guy to confirm but that's what I understood from him.

[Yambo]

Hi,

I'm the C4D guy i made a quick video to show you exactly how it works inside Cinema
I think it's pretty straightforward, if any further explanation needed, let me know.

[aoktar]

Here i'm running extra passes to extract id's with custom assigned render layer assignments. We get gray scale images from alpha output of render layers. I think that's better than to don't have. Excuse me Juanjo for infiltrating to your forum.

[juanjgon]

No problem aoktar, you are welcome ... thanks to everybody for all the information! Let me think about the best way to add this feature to the Houdini plugin.

-Juanjo

[WhyGee]

In case anyone needs a similar workflow for now, currently I render a second time and set the kernel itself to Info Channel with low Max Samples and use the render object layers option in the ROP node as a way to quickly extract clean alphas like in Cinema though it would be nice to have it created along with the single beauty + passes.

Thanks!
Yaniv