Motion Translation

[ZooHead]

I'm trying to translate an objects vertical oscillation to another object that is at a 20 degree angle.
I want the angled object to move on it's object coords, not the global orientation.

So far the Constraint Tags I've tried don't do the trick.

The front shock needs to move up and down at an angle,
while the indicator ball moves straight up and down on a Spline Track.
You can see how the rear suspension follows the ball that rides the spline.

Any ideas are welcome.
I can fake it but it would be much better to figure this out.
Thanks.

 

[ZooHead]

This is the "fake" way.

A separate system at the required angle.

 

[MonkeyT]

Once upon a time (within the last year) I saw a website that had animated drawing of literally hundreds of gear-driven interactions. Unfortunately, I can't find it now.

My suggestion is to look closely at the different ways trains can drive round wheels from the motion of a piston. I don't know the limits of precisely how C3D can constrain the motion, but mechanically, this is my first suggestion.

 

[ZooHead]

I dug up an old "steam drive" test, but the wheel is driving it so it's not really helpful.

Thanks Monk, I guess I need to work on this one some more.

 

[MonkeyT]

I dug up an old "steam drive" test, but the wheel is driving it so it's not really helpful.

Actually, I think it is helpful. Since you say the wheel is driving your model, so replacing the wheel with your curve-driven ball (with the ball moving laterally in this case) would make no difference in the function of the piston. Both joints would move in parallel.

Rotate the piston 45 degrees around its closest point to the wheel and you should still get that piston motion - the difference is that because the piston joint's motion is no longer parallel to the driver object's motion, the displacement along the direction of the piston notion will be reduced proportionately. If this were a generator or a motor, that would mean a serious loss of power, but as a shock absorber, it would merely put additional stress on the mounting points of the piston and on the joints as they moved. In a virtual project, that means almost nothing.

The motion is so close to the motion of your wheel-driven piston, it seems that it has to work. I just don't know enough about constraining the motion of those links.

 

[ZooHead]

Good call, I changed the rotation to a linear oscillation
and put it in a folder at the proper rotation.

 

[ZooHead]

Thanks MonkeyT for keeping me focused.

To be honest I still don't understand why it works, but it works.

Setting it up is not intuitive, some objects must be
created with the z axis along its direction of motion.
It's all done with 3 Parent Constraint Tags and one Target Tag.
When setting up I found with two of the Parent Constraint Tags I
had to uncheck the Maintain checkbox before assigning a target.
Once assigned I can recheck the checkbox with no problem.

I included the file in case anyone wants to play with it. (and maybe explain it)

 

[MonkeyT]

Thanks for including the file. I haven't been able to fight with motion much yet and am struggling with the basics whenever I tinker. This should help tremendously.