how to write expression in such case-4

[Suraiya A]

Hi, 

I want to animate somthing. but dnt know how can I do that. I want to take value for position a to b from a trim path animation. but also I want the postion to be above the trim path. I want to make it look like it's floating. wiggle I applied. but I dnt understand how to write the expression. please help. 

in blue box green bar animation, I applied the expression. but the box is not above the bar, like the second sceneario. How can I make the box take its position value from trim path and also remain to be above. thank you. 

[Dan Ebberts · Accepted solution]

I think I try something like this:

yOffset = -100;
L = thisComp.layer("Line");
p = L.content("Shape 1").content("Path 1").path;
w = wiggle(3,5) - value;
L.toComp(p.pointOnPath(L.content("Shape 1").content("Trim Paths 1").end/100)) + [0,yOffset] + w

You could certainly replacye the Trim Paths End point with a slider if you want to.

[Suraiya A]

Hi Dan, Thank you so much. I did it!! I screamed so loud outta happiness that I think International Space Station's astronuts cud hear me. Thank you. this is so cute.

[Suraiya A]

Hi Dan,

am experimenting. why the expression is not working now?

[Dan Ebberts]

I'm not sure what you're after exactly, but maybe this:

offset = -100;
L = thisComp.layer("Line");
p = L.content("Shape 1").content("Path 1").path;
w = wiggle(3,5) - value;
newP = L.toComp(p.pointOnPath(L.content("Shape 1").content("Trim Paths 1").end/100));
v = p.normalOnPath(L.content("Shape 1").content("Trim Paths 1").end/100);
newP + v*offset + w

You might have to change the sign for offset, depending on how you drew the path.

[Suraiya A]

Hi Dan,

I tried the xpression, it didnt work. I think for closed path it dsnt work. am so sad now. feel like am lost :'(

[Suraiya A]

[Dan Ebberts]

It looks like you left out the 6th line of the expression:

v = p.normalOnPath(L.content("Shape 1").content("Trim Paths 1").end/100);

[Suraiya A]

Yes, My bad. I tried again. it works now, but the ball seems intoxicated. it forgets what it shud follow. 

[Dan Ebberts]

There's definitely something strange going on there. Could you possibly post the project file?

[Suraiya A]

here it is.

[Dan Ebberts]

I think it's because for the line, you have Transform Shape 1 Scale not set to 100%,100%. If you change it to 100%, you'll also need to change the offset variable in the expression from -100 to 100 to get the ball on the outside of the line.

[Suraiya A]

Hi,

Now I set both 100,100 (scale), but its more bizzare 😮 

[Dan Ebberts]

You need to change the first line of the expression to be:

offset = 100;

[Suraiya A]

😮😮now it works!!! 😮 😮 THANK YOU SO MUCH. 😮 😮 😮