Apple Motion: Custom Speed Parameter on Motion Path Does Not Perform as Expected

Question

Level 1

9 points

Apple Motion: Custom Speed Parameter on Motion Path Does Not Perform as Expected

I've used the custom speed parameter many times on a motion path with no issues. But once in a while it just suddenly breaks, I can't find any reason why, and it's driving me insane. I've seen this issue posted in the forums several times and never is there a solution.

Here are my steps:

Add a motion path to an object/group.
Set Path Shape to Geometry and drop a path in the well.
Change Speed to Custom.
Add keyframes.
Depending on the day, it either works, or all **** breaks loose. Deleting the motion path and trying again does not fix the issue. See screenshot for example.

In the screen recording, you can see the red dot moving along a path, completely ignoring the keyframes in the custom speed parameter.

Here's a screen recording.

MacBook Pro 15″, macOS 14.2

Posted on Feb 3, 2024 1:42 PM

Reply

Answer 1

JoePro Author

Level 1

9 points

Feb 3, 2024 2:57 PM in response to JoePro

Here are two screen shots of the keyframe editor, the first showing a custom speed parameter that's working properly, and the second showing one that's not. You can see in the first ones that the transform.x and transform.y curves match the custom speed curve. As the speed curve changes, the x and y change accordingly.

However in the second one, the x and y curves do appear to be affected by the custom speed curve, but not as expected. As far as I can tell, the x and y curves just sort of randomly wiggle around, causing crazy behavior in the motion of the object. I've tried resetting all of these parameters and to no avail.

Reply

Answer 2

JoePro Author

Level 1

9 points

Feb 3, 2024 4:57 PM in response to rowie302

Ok I see what I did wrong. That's a neat trick. Unfortunately, it still isn't fixing the problem. As you can see here, my original custom curve is visible along with the new one created from the text layer, and the transform x and y coords are still doing their own thing.

Reply

Answer 3

rowie302

Level 4

1,296 points

Feb 3, 2024 9:04 PM in response to JoePro

The link out to the sequence text custom speed works.I use it in commercial products without any problems.You will still see the customer speed curve for the motion behavior showing in the editor..however it is now being overridden by the text sequence instructions.

This example demonstrates

If you look at the path of the layer the motion path is applied to, you will see that it matches the curve of the sequence text.

Here is the custom speed of the text behavior

Here is the path of the layer the motion path is applied to

You can see the motion path here

As Fox mentioned, there must be some other variable that is getting in the way here.

Try the sequence text method in a new project, just set it up with something basics until you get it working as it should.

The motion path behavior with keyframes on custom speed has always been problematic, which is why I used this method at all times instead.

Good to see you filed a report.

Reply

Answer 4

fox_m

Level 6

12,595 points

Feb 3, 2024 2:29 PM in response to JoePro

Motion Path, specifically for Custom animation is... a pain in the butt...

When you add a new Motion Path and set the Speed to Custom, —— notice —— that the Custom Speed parameter is PRE-ANIMATED — already keyframed from 0 to 100 — it's the only parameter for any behavior that is like this!!!

If you're want to create custom keyframes, you must first right click on the parameter and Reset Parameter to clear it. THEN you can create custom keyframes for the animation.

HTH

Reply

Answer 5

JoePro Author

Level 1

9 points

Feb 3, 2024 2:42 PM in response to JoePro

Here's another recording, a closeup of the keyframe editor. You can see as I drag the playhead along the keyframed speed parameter, the transform.x and transform.y values are bouncing all over the place seemingly at random, completely ignoring the custom speed keyframes.

Keyframe editor screenshot.

Reply

Answer 6

JoePro Author

Level 1

9 points

Feb 3, 2024 2:46 PM in response to fox_m

I tried resetting the keyframes. I tried manually setting keyframes. I tried resetting the location parameters of the group I'm attempting to animate, as well as the items in the group. It makes no difference. If I change the speed parameter back to Constant, or anything else, it works as expected. But this Custom Speed parameter randomly breaks periodically and nobody seems to know why.

Reply

Answer 7

rowie302

Level 4

1,296 points

Feb 3, 2024 3:50 PM in response to JoePro

Hi JoePro

The custom speed can be linked tp the custom speed of another behavior that has custom speed. Add a text layer and apply a sequence text behavior to that. The custom speed of a sequence text behavior is stable and shouldn't give you the same erratic results. Link the custom speed of the motion path to the custom speed of the sequence text and then use that to set your keyframes. Turn off the text in the layers so it just services as a null source for the parameter.

Reply

Answer 8

fox_m

Level 6

12,595 points

Feb 3, 2024 5:12 PM in response to JoePro

If worse comes to worse, you can "lock" the Custom Speed to 0 (Clamp) and animate the Offset Parameter.

However, the fact that you're having these kinds of issues with Custom Speed means there is something else going on. I cannot reproduce your problem with what you have stated here. I don't have info on what's going on with the rest of your project, or if you just need to simply restart and delete preferences... which is not something I generally like to recommend doing.

Reply

Answer 9

JoePro Author

Level 1

9 points

Feb 3, 2024 5:19 PM in response to fox_m

I appreciate all the advice. In the end I just decided use a more laborious method and change my animation a bit so that I don't need to use custom speed. Not ideal but I'm able to move on. I did file a bug report (after wasting hours on this) with Apple. I see in the forums people have been asking about this same problem at least since 2009. I've made tens of dozens of projects using custom speed, and I'd say about 1 in 10 just suddenly starts giving me fits like this and there's never a resolution. At first I thought maybe I was doing something wrong, but now I'm pretty sure it's just breaking, but why I still have no clue.

Reply

Answer 10

rowie302

Level 4

1,296 points

Feb 3, 2024 4:13 PM in response to JoePro

Make sure the sequence text is set to custom

Add a link the motion path custom speed - add the text layer to that source. Now you should see the speed of the text sequence available in the options

Reply