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  1. Member
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    Jul 2009
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    Hi there.
    I am new to after effects cs4, and I am having some masking problems. I have a video with a person who is falling, i.e I have to make an animated mask. I use only one mask, and when the person moves, I edit the shape of the mask so it fits the person. But when I am editing the mask, it changes the shape of my mask on the keyframes that comes before the one that I am working with. So I have to go back an fix the masks on the other keyframes. I use toggle hold keyframes to avoid this problem, but it does not seem to be helping. Can anyone tell me what I am doing wrong? Probably some dumb little newbie thing
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  2. Don't alter the number of points (vertices), or it will morph and you will have problems - I suspect this is what you are doing

    Keep specific points related to the object (e.g. the corner spot corresponding to the elbow should remain related to the elbow, it shouldn't move to another point, like the wrist)

    You can use different masks if it makes it easier (ie. there is no law dictating you to use only 1 mask)

    Keep as few points as possible, with as fewest keyframes as possible for smoothest animation
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  3. Member
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    Well, I altered the number of vertices, so that would explain it.

    The reason that I am using only one mask, is because I am going to make an outline around my object. Therefore I thought that it would be easier to just work with one mask. But I now understand that it isn't necessarily correct.

    Thanks for helping me out again, poisondeathray
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  4. Member fitch.j's Avatar
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    May 2009
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    Be sure your animating all of the attributes that you are changing. A lot of the time you will need to animate more that one attribute. If you dont have the 'stopwatch' on for ALL of these, then you'll only animate what you do have it on for, and just simplay adjust the others each time. This may be causing you issues if things you do are affecting previous keyframes.

    As for masks, i always find it better to use 6 masks for a person (4 for the limbs, then body and head) This way you can rotate them and move them individiually if only certain parts change. This way if a limb crosses the body to the other side you can simply move the mask, but using just one mask can cause problems. By setting the anchor points at places like the hips, shoulders and neck, you can easily move the masks very quickly to mirror any human movements.

    Hope this helps.
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  5. Member M Bruner's Avatar
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    Oct 2008
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    If I need a changing mask, I prefer the Rabinowitz method (ibid.).
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  6. Member fitch.j's Avatar
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    Originally Posted by M Bruner
    If I need a changing mask, I prefer the Rabinowitz method (ibid.).
    He didn't state that he is keying, so i assumed that he wasn't. Therefore he wont be able to AutoTrace anything using his alpha channel. It is also a very un-adjustable way to mask.
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  7. Member M Bruner's Avatar
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    Neither did I. I also use it for non keying applications as well. Of course, it works very well for keying as well. :P
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