Pause a rotation?

[Tony At Work]

Hi, I'm new to AE.

I have an illustration of a set of gears, some of which are to rotate.

I want to be able to pause the rotation of some of them then start it again.

Any help to achieve this would be appreciated

[Mylenium]

Nothing specifically mysterious about it - basic keyframing. I would strongly urge you to at least read the help or watch some suitable tutorials.

Mylenium

[RobShultz]

I would set a keyframe in rotation where you would like it to pause then move your timeline indicator to the point that you would like to start up again. Click on the keyframe that you set where you would like it to pause and copy it. Ctrl (Windows) Cmd (MAC) C then. Paste where your timeline indicator is. It will pause for the time between the keyframe. You would have to have another rotation keyframe further down the timeline to complete the rotation.

if you go to the navigation arrows by the stop wat you can click on the diamond to set Your pause keyframe.

[Rick Gerard]

You use expressions to tie rotation properties together and then only animate rotation on one gear.

Simple example. Main gear 20 teeth, Driven gear 80 teeth. Align the gears so the teeth mesh then animate the rotation of the main gear.

Now add an expression to the Driven gear that looks at the main gear and multiplies the value by the appropriate ratio. 20 to 80 is 4. It will take 4 rotations of the 20 tooth gear to rotate the 80 tooth gear one time so multiply the Main gear rotation by .2 and reverse the direction by adding a minus sign. If you proceed the expression with a value statement you can adjust the rotation of the driven gear so the teeth perfectly match.

value - thisComp.layer("Main Gear").transform.rotation * .25

Put the appropriate multiplier at the end of the expression and you can accurately mesh any number of gears.

That's all there is to it.

Here is a project file for you to play with. Dropbox - Gears.aep (note: your browser may add a .txt extention to the .aep file. Just delete it.

[Tony At Work]

Thanks Rick,

What I want to do is stop the main gear completely and then start it again in the same direction.

The gear meshing is great, but I don't want anything to go backwards as it stops.

I'm used to 3D apps like Modo,Maya etc and can't get my head around why I don't seem to be able to stop the animation in a timeline

and the just repeat it a few frames later?

[Katie Houghton · Accepted solution]

Let's make it simple keyframes.

1. keyframe the artwork for rotation by turning on the stopwatch. (the picture shows the stopwatch turned on)

2. go down the timeline rotate the the gear to let's say 180˚ it looks like 0x 180.0˚ (I went down 1 second on the timeline)

3. go down the timeline and toggle on the keyframe using your AV column. (The picture show the keyframe toggled on.) This will remember the last keyframe which will hold the state of the gear. (I went down 1 second on the timeline)

4. go down the timeline and change the value let's say to 360˚ it will look like 1x 0.0˚ (I went down 1 second on the timeline)

To turn on your keyframes you need to turn on the stopwatch for that property. What ever the value you currently on will be the value of the keyframe. When you go down the timeline and change the value, if the stopwatch is on then you will add a keyframe with the new value. If you toggle a keyframe down the timeline, using your keys icon usually in the AV column it will add the current value. Since I have no keyframes downstream it adds the same value as the keyframe prior.

1. Stopwatch turns on keyframes and adds a keyframe at the CTI (Current Time Indicator)

2. Changing the value of a property will add a new keyframe if your CTI is not over a keyframe

3. Toggling on a keyframe using the keys in the AV column adds a keyframe at the CTI without changing the value. Whatever the current value is at the CTI will be the keyframe value of the new keyframe. (if you are over a keyframe it will toggle the keyframe off. Delete the keyframe)

Hope that helps.

[Tony At Work]

Got it.

Thanks for the help guys

[Rick Gerard]

The reversing direction was just for a demo. You can keyframe anything. It's AE basics. The expression makes the gears mesh. If your gears touch each other then they need to mesh.

[Tony At Work]

Thanks Rick, got it now.

I was missing how to add additional keyframes in timeline.

As you say basic stuff, but sometimes the obvious stares you in the face until it makes a fool of you, hay ho.