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I have a movieclip singleCircle which is a child of doubleCircle. Both circles are 100% black. Now when I set the alpha of doubleCircle, instead of treating the movieclip as a whole, it seems to be setting the alpha on each of the children, resulting in a darker part where they overlap.

enter image description here

Why does this happen and moreover, how can I set the alpha while preventing this from happening. It seems to me when I set the alpha on this specific object, an overlap shouldn't be visible, e.g. it should treat the object as a whole instead of assigning it to every child seperately

I also tried:

  • putting doubleCircle inside another movieclip container and setting the alpha on that
  • tinting the doubleCircle black and set the alpha
  • cache as bitmap on doubleCircle

all of them result in the same overlap effect

Will Kru
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1 Answers1

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When you set the alpha of a MovieClip, this alpha setting effectively trickles down into all child clips when the clip is rendered. The child clips themselves are separate units that get drawn in turn. This means that one child clip is drawn with its cumulative alpha, then the next clip is drawn with its cumulative alpha, producing the overlap you describe.

If you want to avoid this, try setting the Blend Mode of the parent MovieClip to "Layer" under the Properties tab. This causes the Flash Player to first render the clip as a whole to an intermediate buffer, and only then will it apply the alpha.

Mike Welsh
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