# How do I create a clock with proportional rotation of hands?

I'm trying to better understand how rotation works with layers and parent/child connections.  For example, how would I make a clock behavior?   The setup would be a square video -- say 1000x1000.  I'd create a set of hands in photoshop with the vertex at center.

In the comp, I would want to set up a true rotation ratio between the second/minute/hour hands --  but that already needs a script, right?

Is the alternative to fake it by setting up the rotations on layers independent of each other?  Do the new Behaviors offer a solution?

• Moderator

Behaviors offers a solution.

Animate your second hand. Easy. 1 rotation per minute.

Add a rotation Behavior to the minute hand. Select the second hand's point as source layer, set the correct axis to 0.0166% (1/60)

Add a rotation Behavior to the hour hand. Select the minute hand as source layer. Set the correct axis to 0.8333% (1/12)

The Behaviors should chain, so now changing the speed of the second hand should have everything locked together.

I'll assume you have current Hitfilm Pro.

For users in Express, well, no good way to automate this, but, animating the second hand then multiplying its movement by 0.0166 gives you the last keyframe value for the minute hand, multiplying minute rotation by 0.833 is the hour hand. Six keyframes isn't that bad.

• How ironic.  I was just messing with this the other day, though I didn't actually wire the second hand to drive everything (I had a completely different test going with the second hand, which I might share some time later).  I had the minute hand as the driver, and the hour hand following it via the behavior.  The nice thing with that setup is that it's super easy to set the hour by just changing the number of complete revolutions on the minute hand.  1x = 1:00, 2x=2:00, etc.  If I were to actually make a full clock, I'd probably stick with this anyway, and just keyframe the second hand manually, rather than tying that in via behaviors as well.  If the second hand drove everything, it would drive me nuts trying to set a specific time on the clock by rotating that hand a bazillion times.

• Moderator

@jsbarrett six of one, half a dozen of the other--whatever is one's preferred rig. You could always rig the second hand to the minute hand with a 60x Behavior on the second hand. No need to get manual here.

• @Triem23 Doh!  Hadn't thought of that.

This has all got me thinking even more deeply about building a really robust clock rig that can be easily customized and set with minimal hassle.  Might have to add that to my tutorial list.

• Moderator

I suppose the order of Behaviors depends on if it's a "real time" clock or a "time lapse" clock.

For real time it's certainly better to animate the second hand and let behaviors handle minutes and hours. For a time lapse clock, it's probably best to animate the minutes have and have the behaviors handle seconds and hours.

• You're both amazing -- And Hitfilm is getting excellent.

Is anyone working on a comprehensive Behaviors tutorial series?  Without some explainers it's hard to understand the features.

• Moderator

@Davlon I'm planning a Behavior series, but haven't recorded it yet. Hit-U has been, behind the scenes, attempting some major organization overhauls to see if I can get faster in production and more concise in presentation without compromising detail.

Also,with Behaviors I was going to wait until March. It's just a feeling, but I wouldn't be surprised if more Behaviors came out soon, and it's always annoying when I drop a tutorial and an update makes it obsolete in a month.