Keyframes disrupts "Snap alignment to motion" behavior?

Hello again

Ok, disregard my previous advice.

A quick reproduction of your project example shows that moving the map independent of the car is not going to work.

I also encounter an axis glitch with animating the total group.

The sad truth is, that the motion path behavior is loaded with various quirks - in time you'll encounter them all and learn the ways around them.

In this case, our way around is to animate the group all together - and if you do encounter motion glitch - then just remove the position animation, clone it, and then animate the clone instead.

See here, the first run is the total group animated together, the second is the clone animated instead.

Perhaps Fox_M will be around to shed some more light on this.

I had a look at using the local spline for the path instead of using a path source - same result.

I've done countless projects with motion path involved, and these quirks (unresolved bugs that have been reported to apple many times) have never gotten in the way of completion .

The clone method works. A Camera would work. Anything that doesn't animate the Motion Path will work.

Here's what's happening:

The thick red line is the Bézier line used as the Motion Path Geometry source. It is animated downward across the canvas so that you can see the start point and it moves to the end point.

The thin darker red line is the Snap to Alignment Behavior (when selected, you can see the path being followed.) It's the "path" Motion uses to determine the angle of rotation.

Notice that while the Bézier is animating the Snap to Alignment behavior is **intersecting** the line at the point the graphic under control is at that specific point in the Motion path with respect to time. When the scrolling animation stops, the Snap To snaps to the motion path ( <grin> ). The graphic (a car image in your example - a crosshair in mine) is actually following the Snap To behavior. Since the graphic is being animated to stay on screen, the longer bezier path is being "compressed" in the behavior's calculations to fit the part of the screen that rendering occurs in. It happens a lot in Motion with various behaviors — not a quirk or a bug. Almost all behavior Transform calculations are additive (/subractive) to any other transform parameter animations (keyframes or other behaviors). Just something to keep in mind.

Anyway — straight vertical lines (or lines in the direction of animation) that are being animated and compressing the behavior would cause the Snap To "mix up" the rotational calculations as the motion path speeds + position animation cause a kind of "back and forth" changes in direction.

Hope that explains it...

Instead of moving the Map group, do the following: enclose both the Map group and the Car group in another group, and move that.

As I understand it, the fact that the bezier is moving as well as being written affects also its direction, and that seems to be why the "snap" is showing an apparently erratic er... behavior :-)

As Luis notes, and for future reference, animating the path source for a motion path is going to impact the animation. In your first attempt, you had the path source moving independent of the target - the car But as we see, now that you have everything grouped together, you still have issues....i think because now you just have the map still moving in unison with the car ..so there is no difference

The bezier with the write on applied is the source for the motion path right?

I think I see what your goal is...you need the map to move so that the car does not run out of view..is that correct? Try this...

Have 1 group with the car and the motion path (actually, the motion path should

Have 1 group below with the map. Just animate the map independent. The map can shift relative to the car.

A general observation here is that using anchor points to animate position creates issues especially if you are using behaviors that modify position. (in my experience) Not so much an issue here, but keep in mind for future reference.

If you do need to animate the group with the car and motion path, animating the full group with the path source and the target together will work as Luis has explained.

If you still have issues, feel free to share a link to the project file in the youtube description, we can have a closer look for you.

I am away from my mac now but will have a look at this again tomorrow.