Problem with making snake from line

[Evgenii Chernyak]

Hello guys, could anybody describe me one situation? Coach in video made a moving line like a snake from the line. He made two keyframes for Start and End for Trim Pathses both from 0% to 100%. I followed to him but didnt get right effect, so first have of road snake goes right, but then it starts moving vise verse, from end to start of line.

I added project file to the post. Pay attention to shape "Lines". Right now is doesnt work correctly, but if you will change last two keyframes for END and START (in Trim Paths) from 100% to 50% snakes will work like a want it.

FinalWork.aep - Google Drive

Explain me this magic please.

P.S. I'm so sorry for my English and CC skills so I have learnt After Effects just for two days) !

[OussK]

I don't know if i understand you right but try to create new keyframes following the below picture

you will get this

[Rick Gerard · Accepted solution]

The first thing I suspect is that you have created a closed path. You can check it by selecting the Path in the timeline and then using the Menu Layer>Mask and Shape Path>and simply uncheck Closed.

If the motion is the wrong way then you'll have to make sure the path is selected in the timeline, press G to select the pen tool, hold down the Ctrl/Cmnd key to change the pen tool to the drag selection tool (white pointer) then drag a selection around the other end of the line and then use the Menu to set the first vertex.

The math is also a bit funky on your dashes and gaps, but if the line works for you I guess it's ok.

[Evgenii Chernyak]

You are the best. Thank you. I unchecked Closed and it works!