5 Replies Latest reply on Mar 21, 2012 1:33 PM by Dave LaRonde

    Setting Mattes


      I am trying to set a matte to a lover by using another *.exr file for my cutout.  I can get it to work on my text that I have located on the floor but I can not seem to get it to work on the layer of the two people in the scene.


      The illustration was generated out of 3ds max.  The people are just green screened *.exr's with a matte background. I just inverted the map so you can see what it going on.  You can clearly see that the matte channel is being applied to the 3d layer.  I need it to be applied to the 2d scence so that the people appear behind the chairs.  as you can see, when I used this matte on the text on the floor it works like it is supposed too.


      Can someone please let me know what I am doing wrong.



        • 1. Re: Setting Mattes
          Dave LaRonde Level 6

          That's a nice-looking virtual set.  Two questions:

          1) I see that the layer labeled People is a Targa sequence.  No video camera shoots Targa sequences.  Why not import the original green screen footage, then use Keylight to pull the chroma key and create transparency around the talent?  You can animate garbage masks around the people if necessary.

          2) Were there really chairs in front of the male talent when you shot the green screen?

          • 2. Re: Setting Mattes
            swertz4 Level 1

            2)  A very expensive camera.  Just kidding, the people are a series of IFL images that were imported into 3dsmax and rendered out as a series of exr's.  I like working with exr format more than any other because of how they handle gamma.


            3)  There were no chairs in front of the talent.  That scene is completely CG. that was generated from 3ds max and mental ray. 


            What I am doing here is trying to set up an efficient workflow that uses after efects to insert real footage of people rather than CG people.  I used to use autodesk combustion/toxik to composite stuff like this but I think that after affects is better suited for it.  Toxik is great for compositing the CG scene but not for after affects.


            Anyhow, I believe I have founf the answer.  I put the talent into another comp layer and and put the set matte on the comp layer instead of the talent layer.  Here is another screen shot.  I am sure there are other ways to accomplish this.  If there is I would love to know.


            FYI, this is a 10 second clip from the animation 300 frames.  The reason for this workflow is so I can stay efficient with architectural changes and not have to worry about the after effects to be rendered everytime.






            • 3. Re: Setting Mattes
              Dave LaRonde Level 6

              Using the Set Matte effect is one way to do it, but I think a better-looking workflow would be to use a chroma key effect like Keylight on the talent footage.  You have better control over the edges of the subjects.  You can precomp the chroma key shot if you like. 



              I presume you'll have access to talent footage properly lit & shot for chroma key, using a camera that shoots & records video of sufficient color resolution for chroma key. 

              I also presume you're knowledgeable of the considerations to be taken when shooting and working with virtual sets.

              • 4. Re: Setting Mattes
                swertz4 Level 1

                I am not sure how to keylight footage.  Would you mind explaing that workflow with me?

                • 5. Re: Setting Mattes
                  Dave LaRonde Level 6

                  You apply Keylight to a layer just like you apply any other effect.  Using Keylight can be a bit tricky, and you can't do it intuitively. 


                  Fortunately, there are resources you can call on.  Look at this page.  Find the section labeled "Keying Effects Including Keylight", about halfway down.  It contains links to tutorials on using the effect.  Actually, the entire page is extremely valuable if you're new to chroma keying.  Newcomers usually aren't aware of what it takes to make the process successful.


                  You'll also find Keylight tutorials on the Creative COW, not to mention the tutorial on The Foundry website; they developed Keylight.