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I can't find a solution to my problem anywhere on the web. Maybe I don't know how to search for it.

I have this 2D character that is set up the same way that those cardboard cutout puppets with pins for joints are.

The idea is to give it a ragdoll behaviour from the neck down, its head being the only thing animated. I need this character to be on a 2D plane while in a 3D environment, its head floating around, always facing the camera with its limp body following the movement.

I cannot find a way to combine those tutorials I found about ragdoll physics, 2D physics, bone constraints, armature affected by gravity and make it work.

I guess it's a fairly simple issue to solve but it's become clear that I cannot do it on my own.

Thank you for your future help.

EDIT :

Following the comment of moonboots, I did this simple animation on Moho to show you what I mean.

EDIT II :

Following the comment of Rich Sedman, I used hinge rigid body constraints witch works pretty great. The only issue left is rotation constraints for the body parts so I can avoid things like the elbows bending the wrong way. rotation constraints

EDIT III :

I've solved the rotation constraints issue, I think. I use the angular limits of the Z Angle of each hinge point. I wish there were a way to display those limits in the viewport so it wouldn't be so tedious to adjust.

But another issue showed up. I can't find the good way of moving the puppet around.

  • I tried to parent all puppet parts and hinges to an empty but only the latter move with the empty
  • I tried parenting the parts of the puppet between them (shoe to calf, calf to thigh…) but the all thing goes haywire
  • I tried parenting each part to the corresponding hinges but it doesn't work either and the articulation points are displaced

I understand that the hinge points are supposed to stay where they are at frame 0 while still affecting the puppet, wherever it is but it seems to upset my understanding of how to, ultimately, parent the whole puppet body to my already floating around head.

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  • $\begingroup$ in the video, the head is not the only thing animated, so I guess what you want to do is different from what we see and you need to be a little bit more specific, perhaps with some drwings or storyboard.... for example you're talking about 2D physics, what are you refering to? $\endgroup$
    – moonboots
    Jul 25 '20 at 12:34
  • $\begingroup$ I'm refering to the tutorials I've followed in order to try and solve my problem. One of them was on 2D physics i.e. 3D physics with a fixed camera and rotation and location lock on the objects used for it. As my 2D character is in a 3D world, it didn't do. $\endgroup$ Jul 25 '20 at 14:08
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    $\begingroup$ Rigid body ‘hinge’ constraints would seem like the best way to go. These allow rotation in just one axis. Just ensure they’re all oriented ‘out’ of your 2D plane. $\endgroup$ Jul 25 '20 at 14:24
  • $\begingroup$ Ok, I'm gonna try it. Thanks. $\endgroup$ Jul 25 '20 at 15:16
  • $\begingroup$ Hinge seems to do the job, indeed. Thank you for that! The only issue I can foresee happening while I'm building my puppet is the rotation constrain. How can I constrain the rotation of each element so, for example, the arm would be unable to cross the torso or the head. Am I being clear ? $\endgroup$ Jul 26 '20 at 8:14
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For this kind of work there is amaizing addon COA Tools addon for 2D cutout animation. I just dont see it for 2.8x, but it is still very productive to download blender 2.79 and do it in this version. Tool itself easily creates armature and with simple click you can assign sheets to bones. After riging its easy to open (or Append) in 2.8x project. Just dont forget to convert Blender Internal materials into Cycles (nodes).

Package includes also very helpful script for exporting layers with their positions from Photoshop or Gimp.

To get animation like in your example you can try to use Spring Bones addon.

enter image description here

To get properly rendered animation you have to bake bones animation- search for Bake Action with Visual Keying enabled.

enter image description here

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  • $\begingroup$ I don't know anything about the Spring Bone addon, but it looks similiar to something I've made recently. $\endgroup$
    – Leander
    Jul 26 '20 at 14:22
  • $\begingroup$ Thanks a lot to both of you. I'll review those options and keep you posted. $\endgroup$ Jul 27 '20 at 0:24
  • $\begingroup$ The Spring Bones addon works great! But it took me a while to really get what I was looking for. Should I produce a step by step tutorial on how I did it and post it as answer? Thanks a lot, anyway! $\endgroup$ Aug 1 '20 at 12:36
  • $\begingroup$ Ok, nevermind my last victory, I'm done quite yet. I did something and it went bad. But I'm close! My question about the tutorial as an answer still stands, though, for when I'll be worthy. $\endgroup$ Aug 1 '20 at 13:34
  • $\begingroup$ Sure 🙂 Post step by step tut will be welcomed. $\endgroup$
    – vklidu
    Aug 2 '20 at 15:05

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