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laUcci
Participant
June 2, 2022
Question

How to animate a curved joint in a rig

  • June 2, 2022
  • 2 replies
  • 427 views

Hi. I'm struggling with a very simple problem.

I want to animate a stick figure, with stick arms and a stick hand attached to the arm.

I'd like the arm to move like a curvy piece of rubber, but the only thing I manage to achieve with the bone tool is an angled line with random wobbly deformations.

Isn't there a way to broaden the radius of the elbow joint, in order to achieve what I want? I know I can animate a straight line into a curve using a bezier line, but I can't connect an hand to it (or I didn't manage to).

Here's an image: up there's what I get, down is what I'd like.

Thanks for any suggestions!

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    2 replies

    _keyframer
    Community Expert
    _keyframerCommunity Expert
    Community Expert
    June 2, 2022

    Okay - first check this out...
    https://drive.google.com/file/d/1NrXqgGhO6Ebsx0faTP8vr7YQDjS0F_zB/view?usp=sharing

    Basically, I drew a stroke (arm) and the hand I converted to a symbol with the center point near the wrist and then positioned it accordingly. The arm was "rigged" using the Asset Warp Tool. It's the tool represented by a push pin. If you don't see it in your Tools panel, click the 3 dots (...) at bottom of Tools panel and drag the Push Pin icon to your Tools panel.
    Select the Push Pin (Asset Warp Tool) and start at the "shoulder" and click/drag to the "elbow" and release. Repeat from elbow to the "wrist". Select each "bone" and in properties panel change its properties to "Hard" to "Soft". Inster a 2nd keyframe down the timeline. In this keyframe drag the bones. The video shows you how I get it to curve. 
    Apply a Classic Tween and easing. 


    NOTE: I tried to use Layer Parenting to get the hand to follow the "wrist" end of the arm but of course, it doesn't recognize it since the arm isn't a symbol with a center point. So instead I simply used a classic tween to tween it. The problem is, Classic tweens animate in straight lines. If you use a Motion tween, you cann adjust it to animate on a curve. BUT, if you have nested frames with multiple hand positions, you will not be able to control what frame is visible like you can with Classic tweens. This is where Animate gets REALLY clunky and confusing for anyone new to it.

    Hope this helps. There may be a better way but I have yet to find it. A future update may provide an even better solution so hang in there 😉

    Animator and content creator for Animate CC
      L
      laUcciAuthor
      Participant
      June 2, 2022

      Thanks a lot for your answer and for the video you made, you really did give me some good suggestions and it was very easy to understand!

      The ideal would be to have the hand attached to the wrist, as you say, but having the "rubber" bones it's already a big improvement. I will try to fumble with the Asset Warp, which I had never used before (but I'm pretty new to Animate, I used a competitor product until now).

      Thanks again!

        _keyframer
        Community Expert
        _keyframerCommunity Expert
        Community Expert
        June 2, 2022

        Cool! I'll keep trying to solve it. I use a 3rd party extension that is really powerful but not sure it would work alongside the asset warp tool. I'mm keep trying to find an answer.

        Animator and content creator for Animate CC
          _keyframer
          Community Expert
          _keyframerCommunity Expert
          Community Expert
          June 2, 2022

          What would seem like a simple animation can, as you discovered, be quite complicated. I'm going to do some experiements and time permitting a short video explaining the best approach. Stay tuned.

          Animator and content creator for Animate CC
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