Animation transitions: Difference in effective length between states is too big. Transition preview

I've got an Animator which I can open and use fine in Unity 5.5. However, in Unity 5.6.0b9 (possibly earlier), when I select all but one of the transitions, I get the following error and, obviously, no transition view.

Code (csharp):

1.  
2. Difference in effective length between states is too big.
3. Transition preview will be disabled
4.  

I'm not sure sure what "effective length" this error message is referring to, but the length of the clips is between zero and about ~.5 seconds.

I've also created a case, ID is 883536, where I've attached a small demo project.

 

Hi @DavidGeoffroy,

thanks for looking into this.

I looked at the transitions again. It seems that the error is thrown when both clips are in fact of zero length. This error also occurred in 5.5, so that part is not related to 5.6.0b9.

However, some of the clips that report a time of "0.333" in Unity 5.5 now report "0.000" after importing them into the beta (which happened some time in the past). So you are right, it is/was an import problem (can't reproduce it now - fixed already?).

Anyway, shouldn't it be OK to have transitions between two zero-length clips too? In our case, we are essentially blending poses, so it would actually be most logical to have zero-length clips (i.e. one frame).

-plmx

 

OK, so my issue here doesn't have anything to do with the beta, but rather "zero-length" clips.

Here's my use case:

• We have a hand which has several "poses", i.e. can grab various different things.
• Each pose is a certain skeletal position - but only one, and thus only one keyframe. No animation. There is also one "idle" pose - also with only one position/pose/keyframe. The length of each clip is thus zero (one keyframe at 0:00).
  
• We use a state machine to switch between the poses, thus creating animations, and Mecanim nicely animates the transitions between the poses.

This works very well in Unity, and so far I assumed it was perfectly fine. In particular, I think it doesn't make sense for each pose to have more than one key frame, or to have any length at all. Thus, we have placed the key frame at frame 0:00 (because why place it at any other frame, or have two?), and then we have a fixed transition duration of 0.1. However, I get the warning we talked about, and no preview of the transition, on selecting a transition.

However: If I change the fixed transition duration to 0.5 or greater - keeping the clips the way they are, i.e. at zero length - the transition preview we talked about shows up and looks OK. That this is showing the way it is makes sense to me, since the duration of the transition implies length for the entire transition animation (it doesn't make sense that it doesn't show for <0.5s).

Now you said I shouldn't have zero-length clips. A clip with a single keyframe at 0:00 is reported as having zero length by Unity (in the inspector). Although I wouldn't call it "empty" I can understand the logic of it having zero length. But given my scenario above, what should I do instead?

I can move the single keyframe to 0.01 - then the length is no longer zero. Or I can add two keyframes with the same information. However, both seems counterintuitive because now the clip has a length although it really hasn't - there is still only one pose in there, and it seems like a workaround.

---?

 

Thanks @DavidGeoffroy, appreciate the feedback! If a one-keyframe-clip (regardless of where the frame is) would be treated as a non-zero-length-clip (i.e. with a length of one frame) this would both solve the issue and be (to my mind) more logical.

 

OK, thanks! Will keep an eye out in the next betas.

 

Warning is still showing in 5.6.0f1.

As you said, the warning shows if the exit time is zero, even if it is disabled. I.e., the warning does show for this transition (and there is no transition preview):



But it does NOT show for the exact same transition if the exit time is NON-ZERO, even if exit time is disabled. And, also, the timeline preview is shown in this case.

 

ok, thx for the info!