# Looking to hire Bongo IK pro

I am struggling with an IK animation. I am brand new to Rhino and Bongo but I figured out the animation pretty quickly. The problem is in setting up an inverse kinematics relationship to work the way I need. I’ve wasted two full days on something that an experienced user could probably do in under an hour. Please PM me with your contact info and rate if interested. Thanks.

A IK puzzle is always fascinating . Certainly for apprentices I’m happy to have a look and give a hand.
Please document me through this channel or via luc@mcneel.com (when the project is confidential). For large files you can eventually use WeTransfer or similar.

Hi Luc,

Thanks for offering to take a look at my IK puzzle. It is not confidential so I will upload a Rhino file. This image shows the goal.

There is a carriage that moves along a track. The carriage pulls the blue pivot plate along with it. The pivot plate holds a shaft. The shaft pivots at the end opposite of the carriage. The pivot plate has to stay on top of the carriage but also rotate so that it stays perpendicular to the shaft it holds.

The shaft cannot be “locked” to the pivot plate because as the shaft rotates, it must also “slide” through the pivot plate. (The pivot plate holds the shaft in a hole with a linear bearing so that the shaft can slide in and out.)

Thanks again.

Ray

Here you are : Ray.3dm (221.3 KB)

Below I’ll use the terms I introduce in my “Whys-of-IK” video tutorial (which I hope you’ve watched).
The ‘driver’ (and ‘head’) of the chain is (obviously) the carriage. The constraint is the pivot point of the shaft (I made a tiny spindle to make it manifest but it can as good as well be a line or even a point-object – after all it’s just its pivot that really matters). Since the pivot point should only rotate but not move, a constraint ‘Keep location the same’ is used. It prevents displacement but allows rotation. The first ‘joint’ in the IK-chain is the pivoting plate – child of the carriage - which is made a Hinge (Z-axis). The second joint is the shaft - child of the pivoting plate – made Telescopic hence allowing it to slide away from his parent along the Y-axis.
I hope you’ll gain some insight in IK this way.

Wow…thank you!

I had so many things wrong. I moved the pivot point of the shaft down to the spindle position and designated it as a hinge since after all it rotates on the Z-axis. But you have it telescoping. I have watched several of your videos but clearly I need to watch them again.

Thanks again!!!