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Strange Issue with Expression Control Effects and Precomp
Been having a strange problem that seems to have only popped up recently… using both a brand new and an old (from CS3) project in CS4 (9.0.2).
Please bear with me as I’m having somewhat of a difficult time trying to explain this…
When I use an expression control effect to link to a property in a precomp, everything works fine until I set a keyframe and try to animate the expression control.
For example, I am creating a planet earth using CC Sphere (original I know). The earth image is 2 layers in a precomp (so I can control the opacity of the water and land sections separately). I apply the CC Sphere to the precomp, and everything is fine so far. I now have my “globe comp” set up to use in my main render comp. What I’m trying to do is control the Y Rotation of the CC Sphere effect in my main render comp, so I set up an Angle Control effect and link it to the Y Rotation of the CC Sphere effect (in the globe precomp). This works perfectly fine – I can rotate the globe from my main comp… UNTIL I set a keyframe. Once I try to animate, the Angle Control stops working and the globe will not rotate. Delete the keyframes and it works again.
I had the same issue with another project (which is too complicated to explain here) – it’s a project I use somewhat often that has several precomps so I can swap out the source images. I created it back in CS3 and it always worked fine – until a few weeks ago. Suddenly the expression control effects stopped working – but only if I set keyframes. Without the keyframes they still work (so it isn’t a naming issue). This project has worked for me sevral times in the past, but the last time I tried it all my controls were not working. I though it was just a weird glitch until my globe project mentioned above proved otherwise.
I am on a brand new installation of OS X 10.5.8 with AE CS4 9.0.2 (also a fresh install). No preferences or anything were brought over from my old system. I have tried purging the ram, rebooting, another system even – and same issue all around. Of course I can use a workaround and animate in the precomps, but the expression controls would make it so much easier – if only they were working properly.
Am I missing something here and trying to do the impossible? or is there something wrong here?
Thanks!
Scott -
21 Replies
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By “not working”, did you mean that after you add a key frame of the slider control, sliding it won’t affect the rotation of the earth as it used to when it doesn’t have the key frame?
Then this must have been because the actual value out of this slider control is overridden by the key frame. It makes sense – when you use key frames, you want its value to be controlled by the key frame, not what you manually told it to be. So the earth doesn’t rotate because you only have one key frames — one key frame means constant value throughout the time. Have you tried using two key frames at the beginning and end of the time? You should be able to see the earth rotating between the angles specified by those key frames.Xinlai Ni
Software Engineer, Google Inc. -
Thanks for the reply, but yes – ANY keyframes “break” the rotation.
The CC Sphere effect is in a precomp, with no keyframes. The Angle Control effect is in the main comp. I tie the Y Rotation of the Sphere effect to the Angle Control with a simple expression. When I manually drag the slider control with no keyframes set, the rotation works in the comp viewer. But as soon as i try to animate it with keyframes, it stops responding. The keyframes don’t work, manually sliding doesn’t work – it just breaks.
In my old project, I already had keyframes set for the angle control, and they used to work perfectly (I have old renders to prove it) but when I import the project now, the keyframes are still there, the expression is still linked properly, but nothing happens.
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How did you refer to the value of the slider in your globe comp?
Did you use valueAtTime?Xinlai Ni
Software Engineer, Google Inc. -
I pickwhiped the Y Rotation value of the CC Sphere to the Angle Control effect. I’d paste the code in but I have already used my workaround and cannot mess with it right now. But it is a very simple tie one value to another (and since it is an angle control tied to a rotation control there should be no need to convert the values).
The expression works… as long as I don’t try to animate the angle control. When I slide the control in the effects controls window the globe rotates in my comp view… until I add a keyframe (or several keyframes) — then it won’t even move when I manually slide.
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Just out of curiosity, what you’ve described worked for me perfectly, and I am using the following expression for the globe precomp’s CC-sphere layer’s yRotation property:
comp("Main").layer("Control").effect("Angle Control")(1)and it works both with my manual dragging the angle control or with key frames.
Xinlai Ni
Software Engineer, Google Inc. -
Thanks very much for your time on this…
Here’s what weird (and frustrating!!!) — I just rebuilt the thing to test, and of course, now that I’m asking for help, it works as it should!
The expression is the same one I’m using.
There’s got to be SOMETHING going on in my other projects – but the fact that the old one was suddenly broken is what throws me off. I guess I’ll just keep pluggin away and if I see this again I’ll give an update… but for the moment I’m completely baffled.
Are there any gotchas for this sort of thing? Maybe something specific I should look for in my ‘broken’ stuff?
Thanks again,
Scott -
Just so Scott doesn’t seem like a crazy person, I’ve had the same issue.
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Bert!!! Thanks! I was starting to wonder about my sanity 😉
Did you ever figure this out? Does it ever “go away” or once it happens to a project does it stick? As I’m sure you saw when I rebuilt the globe project from scratch it was just fine, but the original project still doesn’t work properly. It’s really strange! I simply can’t seem to find any sort of pattern – I’ve examined everything and it SHOULD work…
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have you solved this problem?
I have your same issue with Expression control effects but i’m on windows -
Hate to drag something up from the past but I ran into this issue tonight and found this post which describes my issue almost exactly. I spent hours setting up a rig that would be controlled by the expression controls in the main comp. I can see the items in the precomp move when I scrub the sliders but as soon as I key frame nothing happens. Wonder if you ever got down to the bottom of what was going wrong.
Thanks
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