4-bar animation - newbie

BillG

BillG

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4-bar animation - newbie

Hi, folks.
I'm OK with animation of a piece, or animation of an attribute, but I'm struggling with bones, joints, and animation of a mechanical assembly. Could anyone tell me where to look to find out about animating a 4-bar linkage? Imagine a trapezoid in which all 4 joints pivot and one side is constrained. If I animate pushing on one joint, is there a way to make the other pieces follow?

Thanks much

Bill
 
Bones and IK are really designed to animate limbs and not mechanical structures. You'll either need to use bones very cleverly or give up on them and do a bunch of stuff by hand. What you really want is physics...
 
BillG said:
Hi, folks.
I'm OK with animation of a piece, or animation of an attribute, but I'm struggling with bones, joints, and animation of a mechanical assembly. Could anyone tell me where to look to find out about animating a 4-bar linkage? Imagine a trapezoid in which all 4 joints pivot and one side is constrained. If I animate pushing on one joint, is there a way to make the other pieces follow?
Click to expand...

Bill,
A model (.jas file) would help to look at what can/should be done
 
OK, here's a quick model. The idea is to connect the holes in the tabs with a fixed-length bar. When one of the tubes is rotated around the bolt, the bar drives the other to rotate.

Bill
 

Attachments

  • linkage.jas.zip
    27.9 KB · Views: 589
This is the closest I could get. Just scale the folder called "scale me" in it's X axis to make it work. If the mechanism had mirror symmetry it would work, but as it doesn't, the only way I can think of doing it is possibly with some very clever use of IK. I have no idea how though.:confused:
 

Attachments

  • linkage2.jas.zip
    113.8 KB · Views: 568
Last edited:
BillG said:
OK, here's a quick model. The idea is to connect the holes in the tabs with a fixed-length bar. When one of the tubes is rotated around the bolt, the bar drives the other to rotate.

Bill
Click to expand...

Bill,
Here is a solution. Not totally mechanically correct but that does what you wanted : rotating the Input folder rotates the Output tube
 

Attachments

  • Image.jpg
    Image.jpg
    62.2 KB · Views: 862
  • linkage-Final.zip
    54.8 KB · Views: 683
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