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Drifting motion - Is there a better way to do this?

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Shawn Marshall
Drifting motion - Is there a better way to do this?
on May 10, 2011 at 8:28:33 pm

Hi:

I worked up a technique more than five years ago to create smooth, drifting motion for text or other elements, but it seems rather convoluted. I'm wondering if there's a better way to achieve the look I want.

Let's say I want a word to slide in from the right in 15 frames, drift to the left at a steady velocity for 3 seconds, then slide off in 15 frames. I'm setting 4 keyframes.

If I leave the keyframes at their default linear temporal interpolation the movement looks very mechanical.

If I F9 (easy ease) the two middle keyframes the text enters, slows to a full stop, ramps up and drifts, ramps down to a stop, then ramps up to exit. No good; I want continuous smooth motion.

If I use Auto Bezier or Continuous Bezier keyframes the motion is smoother, but the text still slows down noticeably in the middle; I want the text to drift at a constant, linear velocity.

So this is what I do to get the motion I want: I start with my 4 linear keyframes. I open the Graph Editor and look at the speed graph. Here, it kind of looks like an "H", with a high speed at the ends and slower speed in the middle. I hover my cursor over the middle line, and it shows a position speed of 287.71 pixels/sec. I exit the Graph Editor and select the middle two keyframes. I hit F9 to turn them into Bezier keyframes. I right-click on one of the keyframes and select Keyframe Velocity. After being Easy Eased the incoming and outgoing velocities are currently 0. I enter 287 in the incoming velocity, TAB, TAB, and enter 287 in the outgoing velocity.

Now my text is moving the way I want. It quickly ramps down to a constant linear drift, drifts, then quickly ramps out of the drift and off screen.

I go through this procedure many many times in a project to make sure that elements almost never come to a complete stop in our motion graphics. I might be animating text, pictures or the camera.

After using software for a long time you can sometimes get stuck in bad habits if you never learned the most efficient way to do something. I'm all about the efficiency, so if anyone can suggest a more efficient approach to doing what I want to do, please reply.

Thank you.

Shawn Marshall
Marshall Arts Motion Graphics


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Dave LaRonde
Re: Drifting motion - Is there a better way to do this?
on May 10, 2011 at 8:34:00 pm

It's a lot easier than than you think. Convert that second keyframe to an Easy Ease In keyframe via the Keyframe Assistant. You use the Keyframe Assistant to covert the third to an Easy Ease Out keyframe. The motion between keyframes 2 and 3 should remain linear.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Cassius Marques
Re: Drifting motion - Is there a better way to do this?
on May 10, 2011 at 9:31:16 pm

Nupe, that's it...boring I know. I wish there was such a thing as default keyframe influence as I see myself allways using more than 50% (from the usual 33%)

just keep in mind you can change shortcuts to take that time adjusting to a minimun.

For example I use f5 for keyframe velocity f6 for interpolation f7 easy out f8 east in (seemed more natural) and it improved my workflow.

also shift + f3 while having a keyframe selected opens its curve.


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Shawn Marshall
Re: Drifting motion - Is there a better way to do this?
on May 10, 2011 at 10:52:36 pm

Hi:

Thanks for the quick replies, I appreciate it.

Dave, your method does result in nice linear motion in the middle, but there are little blips at those two eased keyframes because the incoming velocity is 0 and the outgoing velocity is 237 (and vice-versa). The faster the text is drifting the more apparent the hitch becomes. It's also more apparent on text moving left or right. It's much harder to see the hitch if I use your approach on text moving along the z axis.

Cassius, I'll try to remember to use Shift-F3 more. The rest of the process is still a bit of a hassle, though.

Thanks again.

Shawn Marshall
Marshall Arts Motion Graphics


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Dave LaRonde
Re: Drifting motion - Is there a better way to do this?
on May 11, 2011 at 3:24:25 pm

The Easy Ease In & Out keyframe assistant should make a COMPOUND keyframe: instead of the typical diamond-shaped Linear keyframe, you'll see that one side of it takes the hourglass shape of a Bezier keyframe.

You may simply have to adjust the bezier side of such keyframes in the Graph Editor to get what you want, but be careful. Save the project before you do it so you can Revert if necessary.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Darby Edelen
Re: Drifting motion - Is there a better way to do this?
on May 10, 2011 at 11:38:24 pm

Your technique is sound, but probably more precise than you need to be. If I use the Graph Editor in "Edit Speed Graph" then I just need to aim for a flat line if I want a constant velocity. For the drifting motion you describe I don't bother to enter numerical velocities and influences, instead I just adjust the points on the graph editor directly to get close to a flat line. However, I do usually set the keyframes to 'Continuous' in the Keyframe Velocity dialog.

Darby Edelen


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Shawn Marshall
Re: Drifting motion - Is there a better way to do this?
on May 11, 2011 at 12:16:15 am

Thanks for the reply, Darby.

I sometimes have made these adjustments by dragging the handles on the keyframes. If I zoom in close and enable snapping I can get the motion I want fairly quickly. That would save me the step of opening up the Keyframe Velocity dialog box and entering numbers.

I was hoping there was a way I could do this without opening the Graph Editor at all. I really don't like the Graph Editor. I remember it was touted as a way to adjust the velocity curves of multiple layers spread over the timeline simultaneously, but I don't think I've EVER had to do that since Adobe switched over to the graph editor six or seven years ago. I much preferred the old method where you could twirl down the velocity curve for a particular layer within the timeline, without having to switch to a different interface (that counts against your undos.) It seems like Adobe could have at least left in that capability while adding the Graph Editor option on top of that.

Shawn Marshall
Marshall Arts Motion Graphics


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Michael Szalapski
Re: Drifting motion - Is there a better way to do this?
on May 11, 2011 at 1:24:39 pm

An idea is to have a null object moving through your comp at the drifting speed. Parent your element to the drifting null and then all you have to keyframe is the fast in and fast out which can be eased without worrying about messing up the drift.

- The Great Szalam
(The 'Great' stands for 'Not So Great, in fact, Extremely Humble')

No trees were harmed in the creation of this message, but several thousand electrons were mildly inconvenienced.


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Shawn Marshall
Re: Drifting motion - Is there a better way to do this?
on May 11, 2011 at 6:52:54 pm

Thanks for the reply, Michael. I will sometimes parent multiple elements to nulls to add a drift to all of them. There might be times when doing that for individual items would be efficient, so I'll play around with that approach, too.

Shawn Marshall
Marshall Arts Motion Graphics


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