photo montage question

[flipside]

Hi,

I'm looking for an option to hide objects partially so that it looks as some elements of a background picture are in front of the objects. I thought there was some technique in max to use some geometry that functions as 'masking geometry' or something like that. I can't find it as I don't know the right words for this. Can anybody help me?

Thanks,

flipside

[Trapezium]

are you talking about matte properties?

[flipside]

No not matte properties (I think). I want to put in a certain piece of geometry that defines which parts of another object should be hidden. I can do it with matte too, but this is also affected by GI calculations and gives slightly other color than the background. I think it is something like 'clipping geometry' or 'masking geometry' or something like that?

thanks!

[RErender]

You could just render the clipping objects seperately and the use their alpha to matte your objects.

[suitaloon]

...or use a camera map on the object so that it reflects some background color in the GI.

[casewolf]

or you render with g-buffer, switch 'render occluded objects' on the objects you like on. then import to combustion as rpf and are able to let them disappear without getting a 'hole' in your image.
I'm not sure if this works with vray, though...