Matte Pass problems

[MoonDoggie]

Friends,
Having a small problem with my matte pass and I can't figure out exactly what's wrong. Here are the steps I'm taking to get this result, I was the fridge on a completely black background with the alpha just around the fridge and it's shadows.

The fridge is not visible to reflections
EVERYTHING else is set to (in vrayproperties)

matte:true
alpha contrib:-1.0
directlight,shadows: true
directlight,affect alpha: true

and my environment is set to black, saving out as Targa non-premultiplied alpha, 32bit, here is the rgb and the alpha it's saving

Thanks for any and all help!
Colin

[instinct]

not sure i got you right. But sounds like you want to hide everything besides the fridge. Looks like you missed to set "Reflection" and "Refraction" (lower right edge of the VRayproperties) to 0. If they are set to 1 (default) the object will be gone but all reflections and refractions are still rendered.

Regards,
Thorsten

[MoonDoggie]

Yes, that's what I'm after. However look in the RGB render, why is it even rendering at all? I'm getting strange blue colors from direct light in the render, shouldn't it be black if the objects are all set to "Matte Object"?

[MoonDoggie]

The blueish light seems to be tied to storing the vray lights outside the windows with the imap...unchecking that makes it not render blueish.

[MoonDoggie]

Still nothing? Anyone have any other ideas?

[RErender]

What are you using to composite them together? The alpha looks weird.

[MoonDoggie]

Composite done in photoshop, and it looks just fine. The odd alpha is actually correct (ignore the bowl, it's been corrected) because it's including the shadow of the fridge as well, but why is the rgb all blueish? If all the other objects are set to matte true in vrayproperties?

[RErender]

Ahh, I thought you were comping on top of a grayscale to test

any shadowmap lights in the scene?

[MoonDoggie]

Thanks RErender for your help by the way.

Yes there are, but turning them off doesn't allieviate the problem. I can get the strange blue lights glow to go away only if I stop storing the vray lights with the imap, but this doesn't make a bit of sense (or alternatively turning off "Shadows" in the matte properties tab in vrayproperties). I'll setup a test scene for download tomorrow to see what I'm doing wrong fundamentally in my comp process.

-Colin

[vlado]

Are you using the irradiance map? If so, what are the settings?

Best regards,
Vlado

[MoonDoggie]

Yes I'm using the imap, single frame,
min -3
max -1
hsph 50
interp. 20
clr. .3, nrm .1, dist .1

light cache
store direct light checked 750 subd

[MoonDoggie]

Bump? My settings are posted.

[vlado]

Can you do a small region render with brute force GI as a primary engine and see if this goes away?

Best regards,
Vlado

[gilpo]

I'm posting in reply to this thread because I think we have the same problem.

Here's my scene rendered out with everything normal. I have a vray sun+sky at default. Physical camera: f-stop 4, shutter 60, iso 400, exposure on. Linear color mapping. Gamma 2.2. The room is fully enclosed on all sides and the camera is inside the room. Ignore the low IM settings.



I select just the room, and apply these settings:



This is what I get (IM primary, BF secondary). Just so you know, my environment background in black:



If I switch my GI to BF/BF, I get this:



This makes no sense to me. I should be getting the three spheres looking like they do in the first rendering, but with a black background. I have been using the matte settings to add objects in post for exterior work, but this is my first go at trying this for interior work and it's not going well. It seems like a bug somewhere to me, but if I'm doing it wrong, please let me know.

This is a very urgent matter as I need to start rendering a matted scene like this on Monday. Vlado, please help!

Thanks!

[Morbid Angel]

Im running a different vray version, however this may also work. Here try this scene, it does what you would expect with the matte.

http://www.novuscom.net/~marina/matte_scene.rar