Chizzer

Q: Composite EFX...How to

Hey All...

A little creative advice if available...

I've been straining my wee brain, trying find a way to do the following...

 

I have a short video scene exported from Sketchup.

It has a 3 rail fence about belly high, with room behind the fence to place talent.

I have shot talent against green screen and am trying to put them into the scene, behind the fence.

 

My thought was to create two exports of the same scene - one with the fence, and one without and then place the talent against the first scene (without fence), then mask the second scene with the fence, over top, thereby putting the talent in between the two scenes.

 

I have tried every configuration of talent on top, talent in between with the masked clip on top, and the other way round, with the masked clip on bottom. So far I have just been masking the area of the clip with the fence... I have tried to invert the mask, etc, etc...

 

This does not appear to be an accurate thought process... lol... without trying to recreate the fence in the green screen shots, anyone have a workflow that would accomplish this?  I also have Motion, but haven't tried anything there yet.

Thanks in adavnce

Chizz

OS X Yosemite (10.10.4), MacHead since 1988

Posted on May 19, 2016 10:37 PM

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Q: Composite EFX...How to

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  • by Karsten Schlüter,

    Karsten Schlüter Karsten Schlüter May 20, 2016 3:45 AM in response to Chizzer
    Level 7 (32,703 points)
    Video
    May 20, 2016 3:45 AM in response to Chizzer

    just a matter of stacking order... , look:

     

    Bildschirmfoto 2016-05-20 um 12.41.45.png

     

    on lowest position: the background

    on top of that: the green screen clip, keyed

    and on top of that: the fence, hopefully rendered with an alpha chanel....

     

    Is your fence a still or a moving image?

  • by David Bogie Chq-1,Solvedanswer

    David Bogie Chq-1 David Bogie Chq-1 May 20, 2016 7:33 AM in response to Karsten Schlüter
    Level 7 (25,777 points)
    Video
    May 20, 2016 7:33 AM in response to Karsten Schlüter

    The critical feature of the fence clip is that it has an alpha channel. I do not know if sketchup will export png or tiff with alpha.

  • by Luis Sequeira1,Helpful

    Luis Sequeira1 Luis Sequeira1 May 20, 2016 8:01 AM in response to Chizzer
    Level 6 (12,085 points)
    Mac OS X
    May 20, 2016 8:01 AM in response to Chizzer

    Karsten has already explained the stacking order.

     

    Do you have access to the original Sketchup file?

     

    If so, you can make it even easier. No need to mask anything.

    Export a version *without* the fence; make a copy of the file, export *just* the fence.

     

    Just as in Karsten's picture, then:

    The version without fence will be the background (lower clip in the stack).

    The talent shot, greenscreen goes in the middle.

    The fence clip goes on top.

    Done.

  • by Chizzer,

    Chizzer Chizzer May 20, 2016 8:00 AM in response to Chizzer
    Level 1 (8 points)
    Mac OS X
    May 20, 2016 8:00 AM in response to Chizzer

    Karsten, David...thank you.

    Both answers got me there.

    Although there are some other export/matching issues out of sketchup - it will export a transparent png file and with the alpha and placement the effect is achieved.

     

    Thanks kindly.