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I have tried a myriad of ways to get a child (ArmC) to have two parents (RivetD and RivetC) but I can't get it to work.

Now I realize that there are ways to "fake" constraints so that they look like they work, but for this question, I am trying to figure out if the Blender constraint system can drive objects with multiple joints like they really would function in the real world.

When rotating ArmA which drives ArmB, is it possible to have ArmC stay secured and rotate at RivetD while at the same time staying secured at RivetC which would then cause ArmB to rotate differently?

Here is the blend file: https://dl.dropboxusercontent.com/u/6647893/Forum_Help/TwoParentConstraints.zip

This is an example of what I am trying to accomplish: https://dl.dropboxusercontent.com/u/6647893/Forum_Help/Angles.jpg

  • $\begingroup$ So is your goal to allow elastic stretch to Arm C? Sliding Slot? Most often you see parallelogram configurations for Real World Objects with 4 rivets ... I have not taken the time to see if this is a absolute requirement. Can the distance between Rivet C and Rivet D be close to zero? $\endgroup$ Commented Mar 8, 2016 at 21:46
  • $\begingroup$ I apologize if my image was misleading. I don't want ArmC to bend or stretch at all. I would like it to produce this affect as it would be in the real world. dl.dropboxusercontent.com/u/6647893/Forum_Help/Angles.jpg $\endgroup$ Commented Mar 9, 2016 at 0:53

1 Answer 1


This is a typical Inverse Kinematics job, is this what you are trying to accomplish? gif

  • $\begingroup$ Yes, that is exactly what I am trying to accomplish and I would like to know specifically if there is a way to do it using only constraints in Blender. $\endgroup$ Commented Mar 9, 2016 at 0:56
  • 1
    $\begingroup$ No, there is no way I'm aware of. Bone constraints are the way to go imho $\endgroup$ Commented Mar 9, 2016 at 1:14

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