2 people found this helpful
Try this. After you convert the rectangle to a bezier path select the pen tool, hold down the Ctrl/Cmnd tool to change from the add point to the direct selection tool, drag the selection over the upper left bezier point, right click and choose Mask and Shape Path > Set First Vertex.
Now animate your side and everything should be fine. The problem is that there appears to be no first vertex set when you create a bezier path from a shape. This happens with all of the shapes converted to paths. If you hold down the Alt/Option key when creating a path from a shape tool a bezier path is created instead of a parametric shape and the problem does not exist.
I'm off to file a bug report.
Thanks guys. I have reported few weeks ago but I guess we have to wait for the next major AE update.
found this little tidbit on :After Effects CC (12.2): what’s new and changed in this December 2013 update | Creative Cloud blog by Adobe I remember now that I read this before:IMPORTANT: When you use the Convert To Bezier Path command to convert a parametric shape path to a Bezier shape path, the Bezier path that is created does not animate well (i.e., interpolation between paths behaves strangely and unpredictably). This is related to path direction and how transformations are stored. For now, you should not use these converted paths for animated paths (interpolation between paths); but, if you do want to try, you may be able to work around the issues by reversing the path before conversion.
it appears this was a known issue. unless they fix it, guess that after your convert to Bezier Path, you should remember to set the first vertex manually. you can do that after the fact BTW.