-
What is the deal with the uncontrollable motion curves?
Shrug. I already solved my issue by doing something stupid and wasteful, but I’d still sure love to know… Just what is the deal with AE’s uncontrollable curves?
I set up a keyframe for position A, set up another a few frames down the timeline for position B. I want the motion to be STABLE at position A for a while, then ease into a rapid acceleration and deceleration for position B, and then remain STABLE at position B for a while.
AE is having none of it. It’ll give me my acceleration/deceleration curve, sure. But remaining stable before and after that curve? Forget it. Keyframes be darned: It’s going to go all over the place.
First thing I tried was setting up keyframes on every single frame before and after the curve. You’d think the motion wouldn’t budge then, right? Well, it does. It literally VIBRATES with the desire to do what AE wants, rather than what the user has gone through the trouble of specifying.
So then I tried eliminating the curve altogether and manually inserting the values it had returned, so that instead of a curve, I have the effective equivalent across the same span of frames. And what, oh, what does AE do? It treats it like a G D curve, complete with the apparent inability to hold steady before and after the motion.
This is rubbish. I “solved” the issue by duplicating my object several times, putting them at position A, position B, etc., and keyframing their opacities so that I did, finally, get the effect I should have gotten had AE’s curves been, you know, controllable.
Maybe I missed the switch, buried somewhere deep in AE’s perferences, that says “Turn off arbitrary motion inexactness”. You know, kind of like how one has to turn off the edit softener in Audition before they can really start doing anything precise.
-
6 Replies
-
Have you looked into Hold Keyframes?
Joey Foreman
Editor/Animator
Nowhere Productions, Athens, GA -
Hi,
It sounds to me like the control handles on your motion path may be going off in the wrong direction.
AE is particularly frustrating and counter-intuitive in this respect since motion paths are edited in the viewer while acceleration curves are edited in the curve editor.
Anyway, what you describe could be caused by setting up a motion path, editing your curves and then going back and changing one or more position of an object on screen. For some reason, AE doesn’t change the angle of the motion path’s control point as you move it. The result is that while the object may accelerate and decelerate exactly as you set up in the curve editor, it will also follow a path that may overshoot its final point or veer off in an odd direction before coming to a rest. This can cause no end of frustration in trying to figure out what is causing the erratic movement.
You should set up your screen to provide camera plus side, left and top views. Zoom into each key frame point on the object’s motion path and make sure the control handles are pointing in the right direction. To get a smooth deceleration without odd jumps, the control handle should point into the same direction as the curve.
You may find that some control handles are turned 180 degrees from where they should be and while they appear to point in the right direction, they are actually pointing in the opposite direction. You will need to use the angle tool (I forget what it’s actually called) but it is the one that looks like a sideways V under the pen tool.
I hope this addresses your problem.
Lars
-
You can set up all the viewports you want and endlessly tweak all the control handles you want, but if you would simply like a layer to come to rest on a path, then start up again along the path – convert the keyframe at which your layer should stop to a Hold Keyframe. Give it some ease. Down the timeline a bit, copy and paste this keyframe and convert it to the type of interpolation you want, ease out, and continue your path.
AE is neither counterintuitive nor confusing once you’ve mastered your toolset.
Joey Foreman
Editor/Animator
Nowhere Productions, Athens, GA -
[Marc Brown] “Maybe I missed the switch, buried somewhere deep in AE’s perferences, that says “Turn off arbitrary motion inexactness”. You know, kind of like how one has to turn off the edit softener in Audition before they can really start doing anything precise.”
It’s actually called “Default Spatial Interpolation to Linear” and it’s in the General tab of preferences.
Darby Edelen
Lead Designer
Left Coast Digital
Santa Cruz, CA -
if you right click on your keyframe, check out the keyframe interpolation settings. ive had similair problems where there is excess motion outside of what i was looking for. a lot of times i solved the issue by setting everything to linear interpolation. i hope that helps.
Craig Davis
Color Bars Communications, Inc.
http://www.colorbarsvideo.com -
Some tutorials that might help:
https://library.creativecow.net/articles/rabinowitz_aharon/boomerang_1.php
https://library.creativecow.net/articles/rabinowitz_aharon/boomerang_2.php
Aharon Rabinowitz
Email: arabinowitz (AT) yahoo (DOT) com
All Bets Are Off Productions, Inc.
Creative Cow After Effect Podcast
Internet Killed the Video Star: A Guide to Creating Video for the Web
Reply to this Discussion! Login or Sign Up