Error (26:269) - Can't paste temporal data to spatial data: When pasting a Trim Path to Null Object

[T3kwabz]

I've been making an intro for about 3 days now and, I've been following videos along the way.

I have now reached a point where I want a flare animation to follow the animation of my stroke:

Then at one point, the person in the video says to copy the mask path into the null object position.

Video: https://www.youtube.com/watch?v=va-OvAdPcck&t

(at around 2:55 onwards^^^)

But the way I've done my stroke is through trim paths instead of mask paths as stroke isn't text, so I couldn't create a mask from it. Furthermore, I thought, there's no harm in copy the Trim Path instead to see if that works. Then the error came.

So I'm asking if there's a solution to this, or if there are any plans to make this possible.

Thanks 😛

[Rick Gerard · Accepted solution]

Despite the nearly 400K views on that tutorial, I would give it a C-. Why? Because it's nothing more than a recipe with no real explanation of the technique. 

Trim Paths is not the path, The path you need to turn into a motion path is the Path in Shape 1. Select the base glow layer and press the U key twice to reveal all modified properties in the layer. Underneath Shape 1 you should see Path 1, then underneath that, you will see Path with a stopwatch. That is the vector path you should be copying. 

You'll also want to look for any changes in the Layer>Transform properties in the Base Glow layer. If that layer has any change to Position, Anchor Point, Rotation, or Scale, the motion path will not line up with the vector path.

One more hint. Sometimes it is difficult to make sure that you have a vector path selected so I always set a keyframe for the Path by clicking the stopwatch, then immediately cut it (Ctrl/CMnd + x). Then I select the layer that I want to follow the motion path, which would be your Null 1 layer, set the CTI (current time indicator) to where I want the motion to start, press Alt/Option + p to set a position keyframe at that time and then paste (Ctrl/Cmnd + v). If you use the set, cut, then paste method I describe you will always get the results you want. Always. 

There is an easier way to get a null to follow a motion path and the position, scale, rotation of the layer does not matter. The path can even be animated. In AE 2018 a Create Nulls from Paths tool was added to After Effects. You find the panel by going to Window menu and looking for Create Nulls From Paths.jsx. Open that and you will find three options. The one you want is Trace Path. Just move to the time when you want the motion to start, select the path in the timeline that you want to follow, then click Trace Path and a new null will be created. A Trace Path slider will be added to the null layer and a loop option checkbox. That is all there is to it. It is a much better option. After you use the Trace tool all you have to do is adjust the keyframes and everything will match up perfectly. 

[T3kwabz]

Thank you so much, your technique worked! Lifesaver 😛 

[Kevin Renaudeau]

This create nulls from paths tools is awsome! it makes controlling a 3d camera so much easier. Thanks a lot!