Found some VFB channels, how do I use them???

[schultzeworks]

I checked this forum, the manual, and online... but no luck on this mystery. In the latest build of Vray, I noticed a few new VFB channels. Most intriguing are Render ID, Material ID, and Matte Shadow.

The question is : how do I access these puppies?

I'm assuming they are for the "next version" and that it will be released "when its ready, Dave" but any other information would be helpful!

[dalomar_cg]

Re: Found some VFB channels, how do I use them???

No the channels that are in there are ready to go right now. There are a few that don't really make much sense since we don't support the features that they they are trying to capture, but the channels themselves still function. There are a few that need to be refined as well.

As to actually accessing them, go to the VfB Channels rollout and add the channels from the list on the left to the list on the right.

I know Matte Shadow will be relatively useless because we don't have a matte shadow material (that will be for the next version). The other two should be good to go, and you can use them for masking out certain objects in post.

A little bit on how the renderID and materialID channels work. They basically assign a unique color to each individual object or material, which then allows you to select those object(s) easily in post. Understand that those channels are not antialiased because that process will result in colors that are not the unique color of either object that is being "smoothed".

[ilay]

Re: Found some VFB channels, how do I use them???

A little bit on how the renderID and materialID channels work. They basically assign a unique color to each individual object or material, which then allows you to select those object(s) easily in post. Understand that those channels are not antialiased because that process will result in colors that are not the unique color of either object that is being "smoothed".

maybe put it in different channels of exr/vrimg. And will have options of AA for channels
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As in RhinoAir object properties, add vray-options to render-id

[schultzeworks]

How to assign Material or Render ID?

I was able to add the Render & Material ID in the VFB roll-out, but where do I go to assign a numerical (render/material) ID to the geometry I need to highlight? I looked in the Rhino properties dialog as well as the Vray material settings. I didn't find anywhere to assign a unique ID called 'render' or 'material,' so I am guessing that without that assignment, nothing will happen -?

My goal is to render the ground plane and background as two separate layers/channels, so that I have more control in post. Maybe this is the wrong approach... so I am open for suggestions.

[dalomar_cg]

Re: Found some VFB channels, how do I use them???

You don't need to add any information in order to use those channels. The IDs will be automatically added to all of the geometry or materials.

I think this might be the wrong approach for this, but I'm also not 100% sure what is. I'd play around with the alpha contribution of the material and save gi solutions in between passes.

I think there is a way to "embed" the channels into an exr, but it would have to be exposed to us through the image writer in the Vray SDK (if we didn't write our own). In the VRimage the channels are there, but you will have to do it all with command line arguments.

All channels that require AA have AA, although since the amount of antialiasing that is used is determined by the final image, not the individual channels, some may be a little "rough". RenderID and MaterialID (and NodeID in the future), are not antialiased as this goes against the actual design of those channels. Specific objects masks should be antialiased, but we have not added those yet.

[Micha_cg]

Re: Found some VFB channels, how do I use them???

So far I understand for composite the "wire color" channel would be most interesting for me. The workflow could be, that the user set a rhino display color (isopharm color at the viewport). All objects with the same color get the same color at the rendered wire color mask. So far I understand, the mask dosn't show the isopharms, it show masks with constant color of the object wire color. This mask should be full antialiased, so that aliasing effects should not avoid a clean composite work. Also DOF blur should be visible at the mask.

For the example I would set all display colors at black except the ground at white and render a wire color channel. So, you should get a perfect mask for ground selection.

But ... this can be done now. At the forum tutorial section I post a little tool for mask creation.