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Roto Brushing a seamless loop! And keying a transparent object...

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Garry Jenkins
Roto Brushing a seamless loop! And keying a transparent object...
on Aug 14, 2015 at 12:04:47 pm

Hi everyone,

Hope you're having a good day and might be able to help!

I'm Roto Brushing the object below so that it can be placed on any other background, and am having a couple of problems:

1) The client wants the bottle to rotate seamlessly and while the original footage they've provided allows for this (it loops perfectly), what inevitably happens is that my Roto Brush efforts reset from the last frame to the base frame on looping, and it jars. I'm wondering how I can tell After Effects to propagate my Roto Brush efforts from behind the base frame (at the start of the clip) into the last frame (or vice versa?), so that it's more fluid?

2) I'm having to key out the green within the bottle so that the whole comp is sufficiently transparent, but I'm having trouble getting a result using Keylight...I'm toying with the clip black and white to keep certain areas (the label, top etc.) solid but there always seems to be some sacrifice with another part of the bottle, say the light bouncing off, or the edges - something, somewhere, becomes grainily transparent that otherwise wouldn't be. Am I missing a trick? Is this something that I can fix with layers of Keylight, or is it natural for it to be a pain considering the subject?



I miss solid objects on clean green backgrounds!! ;)

Thanks for your time,
Garry


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Michael Szalapski
Re: Roto Brushing a seamless loop! And keying a transparent object...
on Aug 14, 2015 at 9:38:55 pm

Don't use the Roto Brush. Use actual masks in AE. You shouldn't need to have a keyframe on every frame though. Make your first and last keyframes identical, go the the middle, adjust your mask, split those differences and adjust, etc. until it's right.

You'll probably need to use several instances of this bottle (some in black and white with various blending modes) to make it appear naturally in front of other backgrounds. This looks like it was shot with a very flat camera profile. Have you considered doing the color correction to the shot first before you key to bring the contrast up?

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Garry Jenkins
Re: Roto Brushing a seamless loop! And keying a transparent object...
on Aug 15, 2015 at 3:25:03 pm

Thanks Michael, great advice, saved loads of time using a mask and helped solve the looping problem too, thank you.

I think I'm getting there with the keying, I did what you said and bumped up the contrast, and am playing with the screen gain, balance, and matte controls and adjusting the colour etc. along the way to make it all blend…it's a bit noisy at the moment…ultimately it'll be output onto a transparent background so hopefully I can get the balance right.

After



Thanks for the help, it's much appreciated, I'm way out of my league compared to you guys!

Garry


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Michael Szalapski
Re: Roto Brushing a seamless loop! And keying a transparent object...
on Aug 15, 2015 at 9:46:16 pm

[Garry Jenkins] "I'm way out of my league compared to you guys!
"


We were all there once. :)

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Kalle Kannisto
Re: Roto Brushing a seamless loop! And keying a transparent object...
on Aug 16, 2015 at 7:20:53 am

Another possible approach is to brutally "over-key" it so you basically get the label, the shape of the bottle and the top but lose most of the subtle reflections, and then add fake reflections onto the glass as a separate layer. You can actually add them behind the object.


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Garry Jenkins
Re: Roto Brushing a seamless loop! And keying a transparent object...
on Aug 16, 2015 at 3:50:17 pm

Thanks Kalle, the edges of the bottle tend to disappear with the reflections but I'll play around with the layers idea, thankyou :)


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