• Apple Motion

  Rotoscoping with feathering in Motion?

  Posted by Tom Valens on February 25, 2013 at 2:37 am

  I’m trying to rotoscope a mask of an interview so I can separate the speaker from the background, and then defocus the background. I can do this in Motion 4 using the Bezier Mask Tool. The problem is that the edge is very sharply defined. If I adjust the “feather” slider it will move the mask larger or smaller, but still with a hard line separation. What I want is a “feather” like in Photoshop where I can adjust the softness of the edge, so it creates a blend at the edge between the masked image (the speaker) and the image below it (the background). I remember doing this in Commotion (RIP), but don’t want to have to purchase something expensive like Silhouettefx. Is this possible in Motion? I couldn’t even find a way of doing it in After Effects.

  Thanks.

  Tom Valens
  Tamalpais Productions

  Tom Valens replied 13 years, 2 months ago 3 Members · 4 Replies
• 4 Replies

• 

  Stephen Smith

  February 25, 2013 at 5:00 pm

  [Tom]
  in Motion 4 using the Bezier Mask Tool. The problem is that the edge is very sharply defined. If I adjust the “feather” slider it will move the mask larger or smaller, but still with a hard line separation…….. Is this possible in Motion? I couldn’t even find a way of doing it in After Effects.

  I can’t think of a way to do that in Motion. Other then to move your control points once the feather is changed. However, in After Effects change the Mask Expansion and that will increase or decrease the size of the mask. Best of luck.

  Stephen Smith
  Utah Video Productions

  Check out my Motion Training DVD

  Check out my Vimeo page
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  Tom Valens

  February 25, 2013 at 7:54 pm

  Thanks for the response, Stephen. Playing around a bit more in Motion, I think I discovered my problem. I didn’t fully understand the relationship between the mask outline and “feathering”. A +50 feather, for example, feathers from the mask outline outwards (50 pixels?) I guess I had assumed it would feather centering on the mask outline. In my case, what I needed to do was to make the mask outline smaller so the feathering would start inside the masked shape and proceed to the background. So by going to Inspector>Properties>Scale, I made the mask smaller (in my case 93%), set the feather to +50, and was able to get a reasonable version of the effect I wanted.
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  Simon Ubsdell

  February 25, 2013 at 8:45 pm

  Don’t forget that you can also set a negative feather which will reduce the size of the mask inwards as opposed to increasing outwards with a positive feather. (Also the Falloff control will affect the position of the feather.)

  Another useful trick worth trying is to apply a blur to the mask which has the benefit of allowing you to feather in one direction more than the other.

  Gaussian blur works well but you can also try the directional blur which can give some useful results.

  Simon Ubsdell
  http://www.tokyo-uk.com
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  Tom Valens

  February 26, 2013 at 1:58 am

  Thanks Simon. Looks like I’ll have to play around more in Motion.
  – Tom

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