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question about 3d stroke, lens flare, and alpha channels
Hello,
This is what I am doing. I have signatures that I have scanned, drawn paths on so that I can put 3d stroke on and animate the signature like it is being signed onto a background video. Then I copied the paths and put them into keyframes in the lens flare position so that it looks like the lens flare is drawing the signature. It looks pretty cool. Anyways, I rendered it out with an alpha channel and imported it into Avid. But when I put the signatures over a video background it just shows the signature signature and a black background, the video background does not show through even though I have an alpha channel. I hope this makes sense. I searched for answers, but no luck. Any ideas? Thanks -
6 Replies
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Avid likes straight alpha, not premultiplied. Did you render with straight alpha from AE?
Steve
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No,
I actually didn’t. For some reason, I thought I read somewhere that Avid likes premultiplied. My mistake. Thank you very much -
I have had this issue when exporting with an alpha channels to Premiere. Unless you’ve ruled this out already, make sure your final comp has an alpha channel as follows: at the bottom of your comp window there are the show channel buttons (red, green, blue, white). Click the white (alpha channel) button. I have found that with certain effects (such as lens flare) I need to do some rearranging to make sure an alpha channel is being generated in the composition. Just a thought..
Steven
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Actually, when I click on the alpha channel button the comp just goes white and there is nothing there. So this is probably why I’m having trouble with it. What did you have to do when you re-arranged stuff? By the way, rendering it with a straight alpha didn’t work. I don’t really know what to do. Thanks
Brandon
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“when I click on the alpha channel button the comp just goes white and there is nothing there.”
Actually, if your window goes white when you click the Alpha chip it means _everything_ is there. No transparency at all.
I’m wondering if you’re using 3d Stroke or Render>Stroke. If you’re using Render>Stroke, be sure to select Paint Style>On Transparent. Otherwise you’re stroking over a solid, which will give you a solid Alpha channel.
Could also be the lens flare if you’re applying it to a solid with the Add mode. If you’re using an Add transfer mode it’ll look great on your monitor, but your Alpha channel will still be a solid white.
Hope this helps you get closer to a solution.
Scott
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I am using trapcode’s 3d stroke. Also, I have been using the add mode with the lens flare. I’ll try out different things. Thanks for you help.
Brandon
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