Rendering Occlusion shadows on Object without visibility

[phix314]

The Use Background shader is what you'll want here.

[Reeder113]

The Use Background shader is what you'll want here.

I applied that to all of the background geometry, but it will only let me apply it IN the master render layer, not the occlusion layer. It will work if I render the master layer, but as soon as I render the occlusion layer it only renders the CG character (no shadows). Any other ideas?

[playmesumch00ns]

Just render out a separate occlusion pass and comp it over your background.

[Reeder113]

Just render out a separate occlusion pass and comp it over your background.

Thats what I'm attempting to do (hence the reason for this post ;) Unfortunately, it seems that you cannot apply the "Use Background Shader" to an occlusion pass. I would like the floor to receive the beautiful occlusion shadows, without actually rendering the floor geometry. I can do it just fine in a regular render pass by applying the "Use Background Shader," but not in the occlusion pass. Anyone else have any ideas? I assume this is a fairly common technique used in film making (especially in compositing).

[bezzeler2000]

I'm trying to render the occlusion shadows of my CG character onto the background geometry. I don't, however, want my background objects to render - just receive the occlusion shadows of the CG character. I have turned off primary visibility on all the background geometry, but I have left "Receive shadows" on. However, ONLY the character shows up in the render. I'd like both the character to show up, as well as the shadows he is casting onto the rest of the geometry in the scene, without the other geometry actually showing up. I'm an Animator, so I'm not great with rendering. Any help would be appreciated. Thanks!


By the way, I'm using Maya 2009.

Mabybe I'm reading the bold wrong. If you don't want to see the geometry in the scene what will the character cast shadows onto? You can't see a black shadow over a black background.

[Reeder113]

Mabybe I'm reading the bold wrong. If you don't want to see the geometry in the scene what will the character cast shadows onto? You can't see a black shadow over a black background.

It will be a composite. His shadow will ultimately be "cast" onto a real, live floor. ONLY the character and one other prop will be digital in this scene. Everything else is a live, miniature set. I want the digital shadows to be cast onto the live set. I have an exact duplicate DIGITAL set which will receive the shadows, but thats all I want..........I ONLY want them to receive the shadows. I don't want them to actually render.

Again, I'm talking about an OCCLUSION pass. I can do this just fine in a regular render by using the "Use Background Shader." This shader, however, does not apply to an occlusion render layer.

[noouch]

Render an occlusion pass (excluding the prop/character) and multiply it with the background layer in the comp.

[MarceloJR]

Hi Reeder113,

If I understand; u should exclude this object from AO shader, is simple, into object properties, G-Buffer, Object ID (put a number diferent of "0")

Then go to AO Shader, Incl./Ecvl. Object ID (Neg. = Exlude) put the number u put for this object but put it as a negative value to exclude.

I hope help u.

Cya
Marcelo Jr

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