“My Smart Magnet Rig works well at Keyframes, but elements float during Tweens as if it is not rigged at all. Is this a bug?”
No, it is not a bug.
This is how Classic Tweens work in Flash / Animate. Elements tween from point A to point B in a straight line.
SMR tools assist posing at keyframes in unthinkable ways, but tweening is still handled by Flash / Animate.
So how do we deal with this and how to make the elements move along arcs?
Since the number of new users has exploded after the release of v.6, and many of them are super excited and impatient to start using SMR right away, we thought it would be appropriate to compile a couple of articles that will give quick answers to questions that seem to be common.
We understand the excitement and impatience, which discovering the wonderful world of Smart Magnet Rigs can cause, esp. to people who have wrestled for years with Adobe's less-than-ideal implementations.
Clean Up, LP Toggle, IK Clean Up
Historically, in the previous decades when Flash was used extensively for broadcast animation production, this process of fixing the arcs was done manually during a 'clean up' pass, when all posing and timing were complete to a satisfactory level. Keyframes were inserted in the middle of tween spans and the positions of the elements were adjusted manually.
This is why many years ago, when we created our 'arcs' command that deals with this issue automatically, we called it Clean Up.
In Flash Clean Up (SMR) is the only way to automatically move tweened elements along arcs.
In Animate 2019 and newer, users also have the alternative of toggling Layer Parenting on. Depending on the specific situation this may be more or less suitable than using Clean Up (SMR).
When using SMR Inverse Kinematics, and feet or hands are pinned, we also have IK Clean Up, which deals with these specific situations.