Two newbie questions.. (alpha clipping info passes)

[caffe3]

Thank you for the reply!!! I really appreciate you taking the time to answer... That's a real shame that it will clip the beauty pass as well.

Because, for instance, say we have a scene where a ball is behind a glass window in the start of the scene. The window is made up of a plane object which has a black and white alpha image in the Opacity channel that looks sort of like this:



The white parts of the alpha image would be fully transparent, and we would be able to see the ball behind it. The animation is that the ball goes through the window, breaking the window and ultimately appearing in front of the window going towards us/the camera. So if one was to use Render Layer here on the ball to separate/isolate it, it would be clipped up until breaking the window. But in reality we can see the ball from start to finish. Even if there was no alpha image, just 100% opacity on the plane layer, we would still get the same results. So basically Render Layer becomes useless if there is opacity in the scene

I really, REALLY hope you guys can leave it as an option (checkbox or whatever) to choose whether we want to see the Render Layer when it's visible behind opacity objects. Because otherwise we wouldn't be able to isolate objects using Render Layer in scenes with opacity. Really we won't have ANY way to isolate those objects, because the Layer Masks works the same. And Object ID's aren't configurable + most times makes even worse edges. So basically we are left with not being able to isolate objects easily, only by chance with Material ID or if the scene contains very few objects (in this case one Ball and not hundreds) then by chance Object ID could work also.

Interesting about the material/object IDs btw. Usually those passes are for masking/isolating in post, yeah. But its limitations currently makes it useful for a few occasions, at best. But this is not something I would worry about IF we actually had a proper way of isolating objects in scenes with opacity materials.

[caffe3]

I'll give you a real-world example for when it's a problem, although I doubt anyone has time to actually read this wall of text:

As a visual effects artist, I often get live-action plates of sets/scenes where there are stuff in the middle ground that need to intersect with CG objects. This could be anything from pillars or actors/humans in a room to a fence in an exterior scene.

Sometimes this stuff can be too detailed to model, so what we do instead is try to rotoscope this or key it to create a traveling matte. We add this with camera projection onto a plane in the scene. And then we can add cg objects that start in the background, partly (certain areas, not always fully) obscured by the traveling matte, and the cg objects animate/end up in the foreground at the end of the scene, in front of the traveling matte.

So to isolate the cg object we use black and white object mattes (in octane I'm assuming that's what Layer Masks are meant to be, and it works as it should as long as there are no objects with opacity in the scene, like the traveling matte or transparent objects). Cinema 4D calls it object buffers.

The object mattes have worked fairly great in the past, except as you already know, sometimes the edges can be roughly one-pixel bad. So that requires tweaking or rendering more object mattes than what should really be necessary, like rendering one matte for an entire group of objects to isolate it from the background, and then individual mattes for each object to color correct and whatnot. Usually for color correcting and tweaking, Object ID's work great, if configurable.

So Render Layer is excellent at this (isolating WITHOUT bad edges, which are even worse if motionblur or DOF is involved), as it is right now, with the beauty/main pass coming out superb! But the info passes don't match. So pleeeeeeeeeeeease, can't you guys make it an option for when dealing with opacity objects in the scene. I mean, if you already have coded it to work both ways, can't it be chosen by the user when which way works best?

[stratified]

I'll give you a real-world example for when it's a problem, although I doubt anyone has time to actually read this wall of text:

As a visual effects artist, I often get live-action plates of sets/scenes where there are stuff in the middle ground that need to intersect with CG objects. This could be anything from pillars or actors/humans in a room to a fence in an exterior scene.

Sometimes this stuff can be too detailed to model, so what we do instead is try to rotoscope this or key it to create a traveling matte. We add this with camera projection onto a plane in the scene. And then we can add cg objects that start in the background, partly (certain areas, not always fully) obscured by the traveling matte, and the cg objects animate/end up in the foreground at the end of the scene, in front of the traveling matte.

So to isolate the cg object we use black and white object mattes (in octane I'm assuming that's what Layer Masks are meant to be, and it works as it should as long as there are no objects with opacity in the scene, like the traveling matte or transparent objects). Cinema 4D calls it object buffers.

The object mattes have worked fairly great in the past, except as you already know, sometimes the edges can be roughly one-pixel bad. So that requires tweaking or rendering more object mattes than what should really be necessary, like rendering one matte for an entire group of objects to isolate it from the background, and then individual mattes for each object to color correct and whatnot. Usually for color correcting and tweaking, Object ID's work great, if configurable.

So Render Layer is excellent at this (isolating WITHOUT bad edges, which are even worse if motionblur or DOF is involved), as it is right now, with the beauty/main pass coming out superb! But the info passes don't match. So pleeeeeeeeeeeease, can't you guys make it an option for when dealing with opacity objects in the scene. I mean, if you already have coded it to work both ways, can't it be chosen by the user when which way works best?

Okay, we had a closer look at the code. There's no real reason not to do it the other way around so we'll port the behaviour of the main render to the info passes. Should be in 2.22.

cheers,
Thomas

[caffe3]

Man, thank you so much! I appreciate it Really glad I chose octane. Quality and speed aside, I doubt there's as great of a support elsewhere