How to create and animate a mechanical crane rig?

Hi,

I have been working quite hard to get a grip on rigging for animation. My goal is very simple, but it seems I did not pick an easy object as my third rig (first being a biped, second a car). It is to have a crane pick up an object and place it in a different location. From the tutorials/forums I have seen, I know that i should have a target empty or bone that the crane follows and another object can be parented to, but I have been unsucessful at setting it up properly. In the attached .blend file, I have a controller bone, with which I want to control the rotation of the whole crane the the length of the pulley. What would the proper setup be?
Attached model: http://dimitarsp.com/uploads/crane_rigged.blend

Here is one of the scenes I am working on.


As you see, I have not achieved having the crane pulley in sync with the moved object and i would need much more time-intense keyframing to get it to “follow”.
(on a seperate note I have since subsequently fixed the small interesctions between the lifted object and the frame, etc, but still struggling with the crane rig)

credit for the crane mesh: [email protected] from google warehouse, spierings crane

cheers,
Dimitar

Couldn’t you just use an Empty where you wanted the crane payload to end up? In the attached file I have added a simple Copy Location constraint to the cargo block. The crane picks up the cargo by animating the Child Of influence from 0.0 to 1.0. Then the crane moves the cargo to it’s destination. Then animate the influence of the Child Of from 1.0 to 0.0 and simultaneously animate the influence of the Copy Location from 0.0 to 1.0.

The crane moves away and the cargo is in a new location.

Attachments

crane_rigged.blend (230 KB)

I set up my new scene, but something is wrong with the constraints on the crane rig. At frame 189, for some reason, the rig flips direction. I tried using local/pose/etc spaces, and inverting the lock track or the follow rotation axes still with the same results. Any thoughts?

cranerig.blend (881 KB)