Why can't a Timeline key frame contain zero Position values?

Questions & Answers
1

I don’t really understand what is going on here. Let me describe it and then maybe someone can tell me what is happening.

If I create an Empty with a Playable Director and add three sub-objects such that they form a “formation” (one slightly forward and to the left, one at the origin of the Empty, and one slightly behind and to the right), and then I create a Timeline key frame, then move the animation playhead to, say, +5 seconds, move all three sub-objects together (not the Empty) and then create a new keyframe, the child that was at the origin of the Empty jumps to the final key frame position for the entire animation, yet the other children animate from the original position as I’d expect. Looking at the curves I can see that the object that was at the origin did not get coordinates “recorded” in the key frame, so it ends up “back-projecting” the final key frame coordinates to the start of the animation.

But if I have the child object slightly not at the origin of the Empty (e.g. 0.001 for X, Y and Z Position) then the animation works as expected for all three children.

So something unusual is happening when a child of an object with the Playable Director on it is exactly at zero origin. It’s as if the key frame cannot contain zeros - but why?

2

How are you adding the 0 key frame? The key frame is usually recorded when a value changes. So if you type in ‘0’, it doesn’t generate a key frame if it’s already 0. Instead, right click a property in the inspector add select ‘AddKey’ in the context menu, which will add a key with the existing value.

3

@seant_unity I have the three objects each with their own animation track. I have them at their initial position (relative to the parent Empty), note that one of them is (0,0,0) relative to the Empty. When I start recording for all three animation tracks, select all three objects, and then right-click the Position in Transform and select “Add Key” it only creates a Position key for the two objects that are not at (0,0,0). The object that is at (0,0,0) does not get a Position key frame and if I open this animation track in the Animation view I can see that it doesn’t have one. This is 100% reproducible for me - every time.

Now if I move the (0,0,0) object to anything else, even slightly, and repeat, then this object gets a key frame.