# Animating a pendulum clock?

#1

Hello!

I have a pendulum model I am animating and I have all of the gears working with xpresso but I can’t quite figure out how to setup the ‘verge’ (part that the pendulum attaches to that articulates against the main ‘escapement’ gear) so that is just ‘works’. I found an older thread on this forum with this person’s C4D example, but I don’t know the approach for the scripting:

I thought about trying dynamics with a hinge connector, but my setup only makes the parts fall in 3D space. There has to be a way with just Xpresso, but I’m stuck on how to apply a sine wave or equivalent to make the motion happen.

Any help would be greatly appreciated!

Thank you,

Ryan

#2

Ok, I’ve learned that the pendulum swings based on the ‘escapement gear’ rotation. So now I have attempted to rotate the pendulum based on the gear rotation. I have it rotating in one direction, just fine…BUT, how can I setup a teeter-totter action of the pendulum pivot so that after say, 18 degrees of rotation, then rotate in the opposite direction (then repeat)? I’ve played with range mapper nodes to no avail as well as the flip flop node, but given my limited xpresso knowledge I’m stuck at the moment.

Thanks!

Ryan

#3

Well, I found this link and it helped get me going.

http://www.today.plus.com/3d/tuts/walkthroughe3-pe.html

My solution is not 100% accurate, but it’s close enough for now.

#4

It is not so easy, but also not so difficult.

This XPresso rotate “Governor_gear” by Time value.

The gear has cyclic and irregular rotation which is caused by “Stopper ends”.
Then I separated the rotation into 2 elements first, to avoid accumulation error.

1. Element A is contineous and regular rotation.
2. Element B is cyclic and irregular rotation generated in “Range Mapper” node.

And the gear is rotated with value A + B.

#5

Wow, thank you for taking the time to look at this. Your example is excellent! I shall attempt to apply it to my scene.

Thank you!

Ryan

#6

Another example with Dynamics.

http://www2.11moon.com/sample_files/20111110/governor_dynamics.zip

It could work, but there are some of “Dynamics noise (error)” in gear rotation. And it may give bit cheep (or weak) feeling to viewers.

#7

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