PDA

View Full Version : Wheel to be driven by a steering bar



ben martin
11-28-2008, 09:14 AM
Today is one of those days,

I can't figure out how to make a wheel to be driven by a steering bar.
See the attached figure to understand.

My objective is:
Moving the steering bare sideways, force the wheel block pivot rotation to follow the Steering bar Null as it moves sideways.

I'm sure it should be easy, I just can't figure it out, I'm completely stuck!

Thanks ,

Ben

biliousfrog
11-28-2008, 09:31 AM
think in reverse...why not have the bar move when the wheel pivots?

ben martin
11-28-2008, 10:03 AM
think in reverse...why not have the bar move when the wheel pivots?
Because that long pool in the middle is going to force the steering bar sideways.
This is a horse wagon type system.

That long pool (where the horses pull) is fixed in the wagon structure (chassis) center.
As the horses turn in the road path, so the wheels to help making the road curve, that's it. :)

RebelHill
11-28-2008, 10:39 AM
bill is right... reversal is easiest...

set up a single null to control the steering.. with the wheels (and frame piece) set to follow/constrain/ expression/whatever, so theres ur steer control... make the null u have a child of the wheel assembly, and use a bone or joint or somesuch in the cross bar using something like positional IK to let it move along a single axis to meet up with the null.

RebelHill
11-28-2008, 10:52 AM
for instance...

ben martin
11-28-2008, 11:00 AM
for instance...
Many thanks for the nice example.
In fact, and looking to it, I just realized that my system is not going to work, unless I make some changes in the concept drawing.
It's a bad concept I've done! :o

Again, many thanks!