Super simple rig

[oliver]

Hey!
I haven't rigged anything for ages and need some advice for something so simple I can't find help online.
Imagine a car (or better a tractor) "standing" on it's rear wheels and walking straight forward (= rotating it's hip to lift the wheels) - no deformation necessary, just simple transformation.
How would I set up the rig (hip + legs) / what solvers would I use? 
I just need initial advice to be able to start fiddling...

[MartinBeh · Accepted solution]

Sounds like maybe three dummy helpers would do this?

Dummy A will transform the left wheel, dummy B will transform the main body of the car, and dummy C will transform the right wheel.

Then B is position-constrained (two targets A and C) such that it remains in the middle between A and C, and also LookAt-constrained (to look at C) so it always remains oriented along the A-C axis.

Then you would animate A and C to make some sort of "walking" motion, and B would follow accordingly.

Here is a quick example:

(if you want to also rotate the wheels to keep their orentation to each other you could also add lookat constrains from the left wheel to the right dummy, and vice versa

Of course you could get more complex by using a set of hierarchical bones that act like the hip and two legs, and link parts of the car to the respective bones to transform them but maybe that already to complicated?

[oliver]

Fantastic! Just what I was looking for - thank you!