View Full Version : compositing question...

02 February 2003, 03:31 AM
Hey, I have a live action shot that I'm mixing some hypervoxel effects with. So I made a rough model of the ground, and I need to know how to make it so that this object will be invisisble, and anything behind it will be hidden as well, so the only thing it shows will be the background footage. I can't just use a plain alpha mask because the particles come in front of the ground object too. They start behind it, come up and over to the front, and I want them to be hidden and only show the background image when they are behind it. I've checked the manual and I'm having trouble figuring out how to do this. Any help would be appreciated.


02 February 2003, 04:11 AM
crap, sorry guys. The manual has just what I want, front projection mapping. Sorry for botherin you.

02 February 2003, 04:14 AM
I'm not entirely sure I understand your question, but it IS nearly 6am here and I haven't slept, so my brain isn't exactly functioning at full capacity :p

Why don't you do the compositing in a compositing package?

That way you could make your own matte in Photoshop (or even render it out as a seperate pass) and then worry about the comping in the comping program? Or is that what you are already doing?

Have you tried changing alpha values for the ground object? On the Surface Editor, you can go to the Advanced panel and set a constant value of 0 for the surface alpha, so that it will not be included in your renders, if that is what you are wanting.

I'm not sure if this helps though, because like I said, I'm entirely sure I understand what you are asking :)

02 February 2003, 04:14 AM
Oh ok, I see you fixed the problem :)

02 February 2003, 05:01 AM
Oh come on Leigh!

You should be a ble to do at least 48hrs before a nap.

Youre still young yet.:thumbsup:

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