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piersc
Participant
November 4, 2023
Question

Creating common tangents between two circles

  • November 4, 2023
  • 4 replies
  • 1157 views

Hey y'all,

 

I'm trying to create tangents between two circles/ellipses in After Effects and can't find anything anywhere on the internet anywhere. I've scoured tutorial vids, AE scripts and expressions but no luck, perhaps I'm using the wrong search terms. If there is an already built extension/plugin for this then I'll gladly pay for it, or if anyone has the javascript math function already (where I can copy to a shape layer that I can then pick whip to two circles on their own shape layers), that would be ideal. I don't know the first thing about writing JavaScript and/or expressions in AE.

 

This is basically what I'm trying to recreate (this was made in Houdini - not a program I'm at all experienced in):

 

https://www.instagram.com/p/CfrsyK7s2GQ/

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    4 replies

    ShiveringCactus
    Community Expert
    ShiveringCactusCommunity Expert
    Community Expert
    November 7, 2023

    Looking at the instagram links, I wonder if there's another way to go about this:

    • Draw a path with as many points as you need
    • With the path selected, go to Windows > Create Nulls from Paths
    • Choose Points follow Nulls.  After Effects will now create a null object for each point.
    • Create circles for each point.
    • Use pickwhips to link each circle to match each null's position.

    With a suitably large stroke and fill, I think that should get close to the animation you linked to.

     

    P
    pierscAuthor
    Participant
    November 8, 2023

    Yes I've investigated this approach but unfortunately it doesn't go the whole way to creating perfect tangents that are responsive to changes of the position and radii of common circles.

    kglad
    Community Expert
    kgladCommunity Expert
    Community Expert
    November 4, 2023

    are you willing to pay for javascript functions that define the equations for the two tangents of non-overlapping circles?

     

    how you would use that javascript in ae is not something i would supply.

    P
    pierscAuthor
    Participant
    November 5, 2023

    I already have the JS functions as it happens, so in need of someone that can translate this into either an expression/s, script or plugin.

    Mylenium
    Mylenium
    Legend
    November 5, 2023

    Unless you show your code nobody can help you or even assess if it's in any way useful/ usable.

     

    Mylenium

    Mylenium
    Mylenium
    Legend
    November 4, 2023

    There is no simple math function for this. It's quite a bit more complicated. It's doable, just not with two lines of code like you seem to think. That and of course there's the AE side on top of the plain math/ code like how you want to create the filled area. That could require more extra work. If you want a plug-in, consider getting Plexus, but otherwise this is just too specific for a canned solution, which I guess is the point of creating a piece of art.

     

    Mylenium

    kglad
    Community Expert
    kgladCommunity Expert
    Community Expert
    November 4, 2023

    in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

    p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.



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