Looping motion path problem

[Steve Davy]

I have a fairly simple scene involving a camera fly-thru on a motion path. I want to make a short sequence that when looped on playback will appear to be continuous and seamless.

I'm about 99.9% of the way there, with the composition perfectly matching at the beginning and end of the sequence (basically the start and end of the motion path) however when I loop a playblast there is a very slight bump at the looping frame (taking into account that I need to remove the last frame which is a duplicate of the first).

I suspect this is something to do with the camera's velocity at this point.

The mo path has parametric length turned off and the U value has a linear animation curve on it so in theory the camera should be moving at the same rate throughout, but in practice I have found motion paths to sometimes be less than consistent. Is there anything else I could be overlooking here, or does anyone have any suggestions as to how to fix this cleanly?

I know there are various fudges and workarounds like baking the camera to world keyframes and editing keys etc. but am really looking to identify the problem at source.

Thanks.

[Stephen]

Whether it's Parametric or not if it's identical on the frames (cycled animation curves ) then it sounds like the end of the curve is not perfectly tangent to the start. 

 I would close the curve to make start : end tangent and then detach   You should end up with three cvs across the break to keep tangency.  

Just FYI.  Parametric is dependent on evenly spaced cvs if you want perfectly linear motion.  But also will stick when you animate the non adjacent cvs.  

 Non parametric is U based so it normalizes the length.  which is why if you animate cvs while the motion path is no 0 or 1 the object will slide upon the curve.  

Hth 

-=s 

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[Steve Davy]

Thanks Steve I realized after posting that tangency was likely the issue so with some brute force manipulation of the last two CVs at each end managed to remove most of the visible bump. Good idea on closing the curve -- wish I'd thought of that!

So far as parametric -- that's always been my understanding, i.e. a non parametric mopath supposedly creates linear motion regardless of curve point spacing, but in practice I have not always found this to be the case?

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From: maya...@googlegroups.com <maya...@googlegroups.com> on behalf of Stephen <stephe...@gmail.com>
Sent: Monday, November 28, 2016 7:43 PM
To: maya...@googlegroups.com
Subject: Re: [maya_he3d] Looping motion path problem