How to rig this simple machine?

Question

So i was trying to make this “unique fan”. I provided the video sample below, it’s bit low res but i think the mechanism on that machine is still readable : Video reference

For anyone there still unclear or cant see much detail in that video, i just made a simulated rig by manually keyframing it to visualize better idea what im asking. Here :

Simulated Rig mechanism

Remember, this is a manual keyframe, and i didn't want to keyframe it manually because its so inaccurate, and i wanted that ARM 2 is staying on that FAN ARM hole. So i think rigging it is good idea.

So i tried to recreate it, but I’m confused about how to rig it. I just did make the bones, parent the model to it. There are 2 armatures, 1 on arm, and 1 is the mechanical arm. but i honestly no idea how to put constraints on it. Can anyone help me? this is my first rig i tried, for learning purposes.

here is the blend file : https://blenderartists.org/uploads/short-url/mt2kRaMVeA2ibumusd1lPG9egEx.blend

here is the simulated rig blend file if you want to see it more clearly the mechanism : https://blenderartists.org/uploads/short-url/zNbCDaWdyi2vwlGtAtVOqfxI3y1.blend

any help much appreciated!

Answer 1

As @MohammadHossein has said, it's important to have the length of the link longer than the driving arm.

I think of this as a 2-bone IK rig, just like a character arm, if you want to look up tutorials on how to do those.

I've labelled the bones by analogy to an arm.

• The Fore Arm bone has an IK bone constraint, target: IK Target, Pole: IK Pole. The chain length is 2, to include the Upper arm.
• The bones, target, and pole all lie in the same plane, parallel to the floor, normal to the axes of rotation
• The IK target is parented to the rotating arm, and is the only connection between the rotating arm and the IK chain.
• The meshes do not need to be in the same plane as the bones.

The differences from a character arm are:

• It's mechanical, no need for deformation, weight-painting. Instead, the mesh-objects are directly Bone Parented to their bones

• There are no poses, no disadvantage in having Empties as your IK target and IK Pole.

The rotation of the driving arm will then result in the reciprocal motion of the fan.

Answer 2

For this rig we should think like a mechanical engineer. we see that the driving force come from that little handle and others rotate with respect to this.

you just need something like this:

actually you need a reverse IK for your setup. keep in mind that for a clean rig you must create all of your bones in the same height which means the same z value.

of course the important point is to have good lengths for your arms to achieve a clean movement. your middle arm should be longer than the driving arm.

the rig could be downloaded here: