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growing a luma matte bigger
hey guys!
i’m looking for the easiest solution to “grow” a luma matte. the simple choker doesn’t work cause i’d have to key it first (i guess…).
so let’s say – for example – i have this very basic set-up:
footage of a white circle on black background. no alpha channel.
what’s the easiest way to make that white circle grow bigger?many thanx!
tanner -
11 Replies
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you can precomp the layer and the luma matte together, then you can apply simple choker to the precomp…
if the set up is as simple as you describe, you could apply the set matte effect set to use luminance for matte. to remove fringing you could add the remove color matting effect, or if the color is solid, just add the fill effect with the color you want. you can then use simple choker to shrink/grow the alpha.
if all you need is a simple circle that is easy to manipulate, you could use a circular mask or the circle effect and easily animate basic properties…
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
[christian tanner] “so let’s say – for example – i have this very basic set-up:
footage of a white circle on black background. no alpha channel.
what’s the easiest way to make that white circle grow bigger?”The easiest way by far would be to scale the layer up. I’m guessing, however, that your circumstances are probably a little more complicated. You could use Channel > Minimax with a Maximum operation to expand the white areas. Or you could use a combination of a blur and Levels or Curves to crush the blurred areas into white.
Different solutions will have different benefits. If there are any specific requirements for your circumstances then let us know and we might be able to offer more specific solutions.
Darby Edelen
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thanx for the help guys! most informative.
what i’m trying to do is actually quite simple. that’s why i got slightly frustrated because i’m convinced that there must be an easier approach to it than the one i pursued.
anyways:
i’m compositing an animation done in a 3d app. i got handed a luma matte from an object in the foreground. at some point during the camera move everything but that foreground object fades to white.
i’m trying to make that object pop out even more by applying a OUTLINE to it – probably black.again – a simple one – but again i’m just trying to find a more simple approach than the one i did – and along the way maybe even learn a thing or two. so far the plan worked…
i, for instance, am applying the luma matte to the footage. then i’m applying a duplicate of the luma matte to a black solid. finally i apply the luma key effect and throw that right underneath my footage layer.
it’d be great to hear your approaches.
thanx again!tanner
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thanx for the help guys! most informative.
what i’m trying to do is actually quite simple. that’s why i got slightly frustrated because i’m convinced that there must be an easier approach to it than the one i pursued.
anyways:
i’m compositing an animation done in a 3d app. i got handed a luma matte from an object in the foreground. at some point during the camera move everything but that foreground object fades to white.
i’m trying to make that object pop out even more by applying a OUTLINE to it – probably black.again – a simple one – but again i’m just trying to find a more simple approach than the one i did – and along the way maybe even learn a thing or two. so far the plan worked…
i, for instance, am applying the luma matte to the footage. then i’m applying a duplicate of the luma matte to a black solid. finally i apply the luma key effect and throw that right underneath my footage layer.
it’d be great to hear your approaches.
thanx again!tanner
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A quick idea that might help…
Have you tried taking your luma matte and applying a shift channels filter? You could set it to take alpha from the Luma – in effect turning it into an alpha matte. You’d then be able to use the choker and other alpha-based effects, (you may need to precomp it, though).
Tristan
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you could probably just add a stroke layer style to the object after the track matte (you wouldn’t need to precomp or anything)… select the layer, then choose layer>layer styles>stroke. the settings are just like the layer styles in photoshop, you can set color, thickness, etc…
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
thanx darby, kevin and tristan. great suggestions.
kevin, your suggestion sounded perfectly easy – until i took it into action…
take a look at the attached image.
my comp is 720×405 sq pix. i made a luma matte out of ae for a test. rendered as a mov and imported it back into ae. used it as a luma matte on my footage and applyed stroke to my footage. that was the result. any ideas?
thanx again.
tanner -
I would use Stylize > Find Edges on the matte and set the blend mode to Multiply to get the black outline. If you need more outline then you can use Channel > Minimax with a Minimum operation or you can blur the lines and use Curves or Levels to tweak the thickness/sharpness of the line.
Darby Edelen
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ouch…
did you render your circular luma matte to a compressed codec, like dv…? it looks as though your luma matte is not very clean. i assume you luma matte from the 3d software would be an image sequence or lossless/uncompressed media file, and would be very clean.
the bottom line may indicate that the matte is not the same size as the footage, again that shouldn’t be the case for a luma matte from the 3d program. it should line up perfectly with the original render.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW -
thank you so much guys for all the input.
and sorry it took so long for me to reply. last deadline was a bit tight…
i gave all your suggestions a shot. to apply the luma matte, precompose it and use the simple joker/fill combo seems to do the trick the easiest for that particular example i think. thanx for the suggestion kevin. i’m still wondering why the simple joker works on that precomp at all…
ah – and by the way kevin – that matte experiment of ours remains a mystery too as the matte was EXACTLY the size of the comp and done as an uncompressed tiff.anyways – thanx again guys. help much appreciated.
tanner
p.s.: any idea how it would be possible to transform that outline into a path? to have a spark/flare/or the like follow that outline for instance? just a thought…
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