Very clear UFO daylight photos !

[hartiberlin]

Hmm,
I always wonder, how they do it with Compter generates programs, that
they put this Ufo behind some trees, so the trees are in the foreground
and partially cover the sight of the UFO ?

This can not be done by a simple Genlock device or program.

Does it somehow work with layers, so they have the picture of the
tree in a front layer ?

Just adding the 2 pictures would not work , as you would
see leaves and UFO mixed, so you need to see only the leaves
at this places, but not the UFO...

But then they somehow have to build masks, so that the tree leaves
must just be in the foreground, but the sky around
the leaves must be transparent, so the UFO can be seen ?
So do they just do these masks on a pixel basis so that it is so
exact or how do they do this masking  in so extreme fine resolution ?

Are some CGI experts here ? IronHead ?
Can somebody explain this in detail ?

Many thanks.
Regards, Stefan.

[IronHead]

This is a layering system called compositing using alpha channel masks.

[hartiberlin]

This is a layering system called compositing using alpha channel masks.

How do you set the masking ?
Must this be done manually for all the leaves pixels ?
This would be a very big work to do this very exact on
a pixel by pixel basis for high resolution pictures !

I guess I have to read this up, how it is done...

Regards, Stefan.

[IronHead]

Few different ways , one is by "auto generate mask"  based on color and shift with per pixel fall off  and pixel tracking . the other is a paintbrush like tool that paints with a mask.
There is another way as well using blocking models  and are modeled in the space of the tree  which will not render but will block the area of the ship so the tree will appear to cover it. Most of the time these blocking models will be used to cast shadows  as you can tell the renderer to render the shadows from the model but not render the model itself. So the model is basically invisible.

Since the sky is blue and  little else is, auto generate would be used in this scene with minor correction using a per pixel brush.

[hartiberlin]

Here is a video about it.
But also looks rendered and overlayedonto the video:

http://www.disclose.tv/viewvideo/777/Chad_Capitola_UFO_drone_C2C/?vpkey=

Regards, Stefan.