Path Constraint - Flip certain frames?

[torbjorn1]

Hi,

I am trying to reverse drive the truck into the parking slot in my animation (see vide, the truck should flip and reverse drive at aproximately ~05 sec into the video). In order to make this work I believe I would need to flip the axis on the relevant keyframes, if there is a solution for such?

[leeminardi]

You can achieve the desired result by using two paths.

In the following example I have used a teapot to represent the truck. Line001 is the bottom path for the truck entering the yard.  It goes from right to left.  Line002 is the top path (backing up). It goes from left to right.    The teapot (truck) uses Line001 for the path for frames 0 to 48 and the % Along Parameter goes from 0 to 100.  For these frames the weight for Line001 is 100 and for Line002 it is 0.

The truck is stationary for frames 48 to 54.  At frame 54 the weights for the two paths reverses. That is the weight for Line001 is 0 and Line002 is 100.  The % Along Parameter goes from 100 to 0 for frames 54 to 68. Having the second path go in the opposite direction of the first path ensures that the truck doesn't flip it orientation.

Here we see the teapot at frame 26  while entering the yard.  Note the weight for the two paths.

And here at frame 65 while"backing up".