Matte material for interior scene

[Tom Hamelrijckx]

Hello everybody,

 

I'm experimenting with matte material, but I'm stuck with something.

 

I would like to render an object so I can integrate it in an existing photograph of an interior scene. So what I would like to have, is the object fully rendered, and the shadows on the surrounding scene, like on picture 2. The box below has a matte material, which gives me the desired result.

 

However, this picture is rendered in an open scene, without anything surrounding it, so the GI isn't correct for placing in the interior scene. So what I do is create an opened box that represents that interior (like in picture 3), and hide it for the camera. That results in picture 4. As you can see, the shadows make the matte material of the box below completely visible, and that's not the purpose, I would only like to see the shadows and color bleeding of the green box. How can I do this?

 

In an exterior scene it seems quite easy, but for an interior, I can't figure it out because the matte material will always receive shadow from the box that represents the interior.

 

Thanks for helping me out, I hope I made myself more or less clear, it has been difficult to explain :-)

[Tom Hamelrijckx]

OK, that obviously wasn't clear, let me put it otherwise.

 

Can somebody give me an example of matte/shadow materials in an interior scene (with GI). Maybe post an image and give a short explanation?

 

Thanks again...

[shaneis]

So I'm assuming that you need the green thingy to cast and receive shadows (self-shadowing and from the interior "walls").

 

I also assume that you need the blue base thingy to receive shadows from the green thingy, but not from the interior "walls" and to receive the green thingy's colour bleed.

 

So, green thingy is affected by and affects everything in the scene, whereas blue thingy is affected by green thingy only.

 

Now, I use Maya so my descriptions are going to need translating on your end, but here it goes...

 

A) In Maya, we can break the links between objects for light and shadows.

B) With this in mind, I would leave the shadow links between the green and blue thingy's as they are.

C) I would disconnect (break) the shadow links between the interior walls and the blue thingy.

 

This way, the blue thingy will only receive shadows from itself and the green thingy and also receive colour bleed from the green thingy.

 

Hopefully you can translate that into the app you use, or saving that, someone can interperet for you.

 

G'luck,

 

S.