Why do Motion Tweens fail when tested?

Question

I have created a motion tween in CS4 that works perfectly when scrubbing with the playhead. However, when testing, the motion tween fails yet the rest of the animation plays perfectly. Does anybody know of any issues that could cause this?

Answer 1

Ned:
Thanks for sticking with me through this. Yes, I'm aware tweens are not new. It is the new way that Motion tweens are implemented in CS4 that I am talking about, not what are now known as classic tweens. Anyway, I figured it out and for the sake of the next Flasher that experiences this issue, I'd like to explain how it got solved. I have rarely developed a Flash project where I animated on the timeline. I always did my animation programatically and used only the first frame of the timeline to make everything happen. This meant that dynamically loading symbols and assets from the library required instantiating and loading these assets with actionscript and linking.
For example, if I had a movie clip named thisMC_mc in the library, I would export it to actionscript under the properties menu and give it a class name such as ThisMC. From there, in the document class I would tell Flash I was going to use it at some point by instantiating it at the top of the class like so:
public var thismc:thisMC = new thisMC();
Once this was done it was in scope and I could load and manipulate the movieClip at any time using the name thismc.
So, why did my Motion tweens fail on this project. Well, there were times I would place a library symbol on the stage at authoring time and since it was already on the stage, I did not need to instantiate it as shown above. I just needed to make sure it had an instance name in the properties inspector. And because I did everything from the first frame of the timeline, the MovieClip remained in scope. With this project, I just thought that principle followed through to other frames on the timeline as well. If they were placed on any frame during authoring time I figured they were in scope of the document class.
Apparently, this is not the case. because the tweens would not function when testing. As soon as I started thinking in programatic animation terms, the first thing I did was to instantiate the tweened MovieClips in the document class as shown above. The tweens started working like a charm. This probably occurred because there are event listeners and code in the document class associated with the tweened MovieClips.
I can only assume this issue has to do with scope and that I missed it because I rarely use more than one frame for animation so I wasn't thinking about it correctly.
If anybody can shed more light on exactly what went on it would be greatly appreciated.
By the way, I actually like the new way of doing motion tweens in CS4. It only took a little studying and it all made sense. They are actually easier to set up and I love the fact that you only need to work with one instance all the way through the tween and the tween is not broken up by a bunch of keyframes. I have found that most hardcore Flashers complain about something everytime a new version is released. Mostly just because they are used to the current version and now they are out of their comfort zone. CS4 is a major change but now that I've been working in it for about two months I don't want to go back to any earlier versions. So go ahead and upgrade, once you get use to it I think you'll love it.