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null follow autotraced mask

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Susan Lan
null follow autotraced mask
on Aug 25, 2015 at 6:39:44 pm

I have an autotraced mask, and I want to make it appear while some particles are outline its form.

I wonder, how can I make, (with expressions or something) the object null follow the surface of a autotraced mask?

(in order to then conect the particles to the null)

or the only way is moving frame by frame the null around my complex mask?

Thanks


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Dave LaRonde
Re: null follow autotraced mask
on Aug 25, 2015 at 7:08:37 pm

Is this one, single mask?

Does the layer with the mask have the same horizontal & vertical dimensions and the same pixel aspect ratio as your comp?

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Susan Lan
Re: null follow autotraced mask
on Aug 25, 2015 at 8:56:31 pm

the autotraced mask contains 10 mask (because of the form) this is the from that I converted to "autotraced mask":
https://www.dropbox.com/s/9crfoiq0z7lne1n/1a.jpg?dl=0

this is the autotraced mask:
https://www.dropbox.com/s/ez6mczoc6bn014x/2a.jpg?dl=0

the layer that contains the mask is same dimensions as the comp (I don't know how to see the aspect ratio),

thanks


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Dave LaRonde
Re: null follow autotraced mask
on Aug 25, 2015 at 9:29:16 pm

That's a messy mask, but the overall shape is very easy -- it's an ellipse! You're just shooting out particles, which isn't very precise, so I don't think there's much of a need to get all complicated. Just make the emitter follow an elliptical path. It it doesn't do the trick for you, write back.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Susan Lan
Re: null follow autotraced mask
on Aug 26, 2015 at 9:17:05 am

Thank you Dave LaRonde, but in this video, at minute 00:14:30 turn a "circle" preset into the size he wanted, can we use that preset and turn it into ellipse?
http://www.videocopilot.net/tutorials/the_ring/
I downlowd the free preset by downloading te proyect, which is at rigth lateral in that vide link, can you help me to do that, please Dave?

Because the other solution of manually keyframe, frame by frame the ellipse form, perhaps it will not be so "organic" movement...


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Dave LaRonde
Re: null follow autotraced mask
on Aug 26, 2015 at 3:12:16 pm
Last Edited By Dave LaRonde on Aug 26, 2015 at 5:41:38 pm

I'm sorry, but I am at work right now and I can't take the time to watch a long explanation.

But you can do this:
  • Create a solid that has the identical horizontal & vertical dimensions and pixel aspect ratio as your comp.
  • Set its opacity to 50%.
  • Put your complicated matte below it.
  • Highlight the solid, and create an elliptical mask that is close to the shape of the complicated matte.
  • Double-click on the mask to activate the Free Transform tool -- you can now fine-tune the elliptical mask. This mask will become the Motion Path for a Null object.
  • When you are pleased with the mask, make a Mask Path keyframe.
  • Create a null object. Leave it 2D for now.
  • Highlight the mask path keyframe you made earlier and copy it.
  • Create a position keyframe for the null.
  • Highlight the position keyframe and paste -- you are pasting the mask path keyframe information into the position property.
  • You will see that a 2-second-long motion path is created for the null. You can make it longer or shorter and you can loop it if necessary.
  • Make the null object 3D. You can now use the null object as the point for the particle emitter.
  • Turn off the eyeball icon for the solid. You are finished with it.


Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Susan Lan
Re: null follow autotraced mask
on Aug 30, 2015 at 12:43:31 pm

In this step:
"When you are pleased with the mask, make a Mask Path keyframe.Highlight the mask path keyframe you made earlier and copy it."
I don't know what do you refers to. I have make a maks into de solid (which opacity is 50%), here is:
http://i.imgur.com/FKwzpOb.jpg
now, how to create a "maks path keyframe" over the yellow mask? in another new layer?

And when you say: "Create a position keyframe for the null." I must to keyframe (frame by frame the null, but, I can't directly copy and paste the keyframe mask into the null without having first tio keyframe -frame by frame- the position of the null? Help, please...


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Susan Lan
Re: null follow autotraced mask
on Aug 30, 2015 at 12:57:25 pm

Whe you say "make a Mask Path keyframe" you mean That I have to anymate the mask with keyframes? I want the null (which emit particles) runing over the mask, ligth this,http://videohive.net/item/the-lights/2611890
I I have to animathe the mask? I don't understand what you mean with "make a Mask Path keyframe" over the elliptiocal mask I've done?


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Susan Lan
Re: null follow autotraced mask
on Aug 30, 2015 at 6:32:54 pm

Oh!I have just realised what do you mean! :)

It is correct? when you say "When you are pleased with the mask, make a Mask Path keyframe"... do you mean to put keyframes inside the parameter "mask shape" of my ellipse mask?
http://i.imgur.com/yu80keN.jpg

(I was thinking that you said that I must create a second mask shape over/on the ellipse mask created before)

We want to keyframe the parameter "mask shape" of the ellipse mask,in order to make the sensation that the real "form" appears slowly?

what number I must change (in the capture) to keyframe the "mask shape" of the ellipse mask, in order to make the sensation it appears (while the null emits the red particles?)
here the capture:
http://i.imgur.com/I95NhG6.jpg

Thanks


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Dave LaRonde
Re: null follow autotraced mask
on Aug 31, 2015 at 4:10:07 pm

You DO NOT animate the mask. You make ONE Mask Path keyframe. You use this mask path keyframe to create a Motion Path for the null object. You do this by copying the mask path keyframe and pasting it into the null's Position property.

Try it. It works.

Dave LaRonde
Promotion Producer
KGAN (CBS) & KFXA (Fox) Cedar Rapids, IA


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Susan Lan
Re: null follow autotraced mask
on Sep 6, 2015 at 3:52:04 pm

Thnaks you Dave!

Then, when you said: "You make ONE Mask Path keyframe" = that mean only to create the ellipse mask (without put any "keyframe") I was thinking that I have to create in the paremeter "position" of the mask, a keyframe path. Then, the "keyframe path=the mask itself"

and when you say "create a Motion Path for the null object2 that means only to copy-paste the "position" of the mask, into the 2position" of the null.

Correct? Thanks


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