• Adobe After Effects

  Black line around mask

  Posted by Kar Bon on February 10, 2016 at 12:45 pm

  Hello all !

  On a video made with Keyshot, I want to place a towel around a blade.

  To do so, half of the towel should be behind the blade, and the other half should be in front of it.

  To do so, I have created one “addition” mask on the blade. I then copied the layer containing the addition mask and paste it.
  On the paste layer, I changed the mask from addition to “subtraction”. The shape and movement of both masks are thus exactly the same.

  Here are pictures of the addition and subtraction masks.

  
  

  But there’s a problem. On AE composition and on the rendered video, I get this black line around the blade.

  

  How could I remove it, or at least make it less visible ?

  Thank you very much in advance.

  Sean Mcgarry replied 9 years, 10 months ago 3 Members · 3 Replies
• 3 Replies

• 

  Cassius Marques

  February 10, 2016 at 12:51 pm

  have you tried to choke the layer by some fractions of a pixel? (simple choker effect for ex.)

  Cassius Marques
  http://www.zapfilmes.com
• 

  Kar Bon

  February 10, 2016 at 1:05 pm

  Thanks for your answer Cassius !

  I actually found out why there’s a line around the blade. I kept the addition mask but I deleted the subtraction mask (kept the layer though).

  I don’t know why I used subtraction mask actually, now it works !
• 

  Sean Mcgarry

  October 26, 2016 at 9:08 pm

  In my case I had an effect on the video or photo layer and when I tried to mask out a section it left a thin dark line around parts of the mask. I fixed this by pre composing the video with all attributes included, then applied the mask to the pre-comp.

  Hope that saves someone some time…

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