Controling the velocity of rotation.

[christian151276]

Hello,

I am looking for a way to control the velocity of rotation when rotating a text character on its Y-Axis. 

My intention is to have the individual text character animate in from one side of the screen while spinning on its Y-Axis, once the character has arrived at its final position I would like to gradually slow the rotation down so on the final frame it flips into place, repeating this for each character, creating a domino like effect and revealing the word.

I have tried using the speed graph to control the rate of spin but it does not give the desired effect.

Is there away to achieve this affect in after effects?

[Mylenium]

Sure, but you likely will need to animate each letter as its own layer. Some animation patterns are simply beyond what you can achieve with text animators due to how the apply their magic relative to the entities, not in absolute space.

Mylenium

[christian151276]

Thanks Mylenium,

All the text characters are on individual layers and are animated individually, I just can’t seem to gradually slow the rotation speed for each layer.

[P.M.B]

THIS IS ALL WRONG.  I used to know how to do this. I have to figure it out.  Everything below is incorrect

You could rotate the characters via time expressions and then connect the multiplier to a slider control which you animate one to zero.

So you would create an expression on the Y rotation something like time*13   You can play with the value to get the rotation speed you want.  I am just using 13 for the sake of an example.  Then you create a null or solid and apply the Effect>Expression Controls>Slider Control.

Then edit your expression to (time*13)*    Place the cursor right after the final multiplication symbol use the expression pickwhip to connect to the slider value.

Now your expression should look like this (time*13)*thisComp.layer("Black Solid 1").effect("Slider Control")("Slider")

Set the slider value to 1.  This will multiply 13 * 1 resulting in a rotation speed of 13,  Now you key frame the sliders value down from 1 to 0 which will gradually slow the rotation down.  When the slider value reaches 0, 13 will be mu;tiplied by zero resulting in a rotation speed of zero.

So now here is video going over the general principle.  The example is slightly different as it is using a wiggle expression on the position rather than a time multiplier on rotation but hopefully in combination with my above explanation you should be able to work out to get it done.   Control Expressions with Sliders in AE | PremiumBeat.com - YouTube

Hope i didn;t forget anything.

ACtually my example is overly complicated.  You can just use the expression time*#value  then pickwhip value to the expression slider so the expression looks

like this time*thisComp.layer("Black Solid 1").effect("Slider Control")("Slider")     Now you control the speed with the slider and keyframe down to zero to stop it.

[christian151276]

Evening Gutterrfish,

I know you said that your explanation was in correct but just out of general interest I tried the above using the expression and the slider and it did created the effect I was looking for, well sort of.   I found that once I had set the keyframes and ran the effect it gradually slowed down as planned but it reached what looked like the 0 point halfway through the set duration then it sped back up again, spinning in the other direction.  To freeze the character as in the image below I had to add a key frame just at the right point or otherwise the character would have been facing the other way.  

The formula I used: (time*1440)*thisComp.layer("Slider Control").effect("Slider Control")("Slider").

[Rick Gerard]

This is a piece of cake with the speed graph and 2 keyframes. I set the y rotation to 6 in about 4 seconds, opened up the graph editor, selected the pen tool and did a little dragging. Took about 2 minutes:

When you drag the bezier handle on the right side you have to make adjustments on the left. Once you get the hang of the speed graph, not the value graph, things like this are very easy to do by hand.

Just multiplying time by the slider won't give you as much control over the curve and could make the rotation reverse. If you want to use expressions to control the speed of anything you should look at Dan Ebbert's Expression Speed and Frequency Control.​ That's the only way to gain complete control over speed and time using an expression. The first two or three paragraphs explain why just multiplying time by a slider will not work very well.

[P.M.B]

Thanks Rick for that link.  I've bookmarked it.  Funny how the first few paragraphs explains perfectly my logic, process & horrible feeling when the rotation reversed itself as if he'd been looking over my shoulder.

[P.M.B]

Yes.  Not sure if I'm expressing this correctly but the reversal of rotation was the problem due (I think) to how the rotation is in linear degrees.   I've  suspected some expression would be needed to control the rate of change over time.  I feel this is a common expression that I have seen or learned in the past but cannot remember and have not been able to find (maybe Rick's link to Dan Ebbert's page will confirm this).   The reason I left the post up was because I hoped there might still be some value in it as in all mistakes have the potential for learning.   

And thanks Rick for that link too.  I will be reading through when I have a few minutes.