Matte Reflections and Shadows on Ground - Composite?

[davision]

So, is there a way to create a rendering in Vray which allows you to composite a rendered object along with it's shadow and reflection (on a matte ground plane) into a photo in one pass?

Since the reflection doesn't have an alpha and the shadow does, it seems a little tricky -- at least as a single pass process.

[natty]

hi
yeah very simple

make the object invisible to the camera.
make a plane got to vray option and tell the plane to be a matte object to recieve shadows and reflections ...and thats it.

[tom schuelke]

Hi

If you wonder how to , just go to the vray system settings in the renderer dialog, in the object settings youll find the options for mate shadow objects.

other way, use the vray wrapper material to tell objects (in this case the materials) to be mate shadow.

and by the way, it is much more straight forward than matte shadow of max standart.

you can do it with gi, softshadows, gi shadows, and also reflections of environement.

Tom with greetings from Hamburg

www.lichtecht.de

[davision]

I don't get it. I know the matte shadow function but the problem with what you are saying is that the object itself will be invisible. I want a full-color rendered object, its shadow and its reflection... All in one pass.

I don't think it can be done though since reflections are best composited additively and shadows and regular renders shouldn't be. I guess reflections need to be treated separately..?..

[trixian]

Maybe I'm bing rather dense here, but doesnt the answer to your question lie in the question it self?
Render your object with shadows and refletions out as a 32 bit image, and comp it over your desired BG plate. Or alternatively, place your favourite bg plate into your max scene through the environment dialogue. Add some matte objects that mimic your BG plates surfaces so they recieve the correct shadow etc.
Or are you trying to achieve something else? If you want everything in one pass that is?

[davision]

To be honest, the original question is a few weeks old so I may be forgetting something. But as I remember it -- the problem was this: If I want to composite the render in a separate program, the alpha channel only reveals the rendered object and the shadows. The reflections are ignored by alpha so the compositing program doesn't show them at all.

You're right, if I used a BG plate in max itself there would be no problem, but I want the control of using a compositing program (AfterEffects).

I did solve the problem by using a second reflection pass and just compositing it with the Screen Blend mode in AE. My question was just asking if there was a way around using a second pass since it slows down workflow a bit.

Does that make sense?