[Filip Vandueren]

Well, after some experimenting, it turns out this is not a flaw in the expression, but a serious bug in After Effects…
I’m not sure how and if one can work around it.
see the post “Headscratching 3D error: Z-position”
at https://forums.creativecow.net/cgi-bin/new_read_post.cgi?forumid=2&postid=859101&theadid=859099&pview=t

Perhaps best then to go with the tutorial you had.
Could you post the url for the original tutorial, then I’ll have a go at rewriting the expression for 3D

[Filip Vandueren]

Well, after some experimenting, it turns out this is not a flaw in the expression, but a serious bug in After Effects…
I’m not sure how and if one can work around it.
see the post “Headscratching 3D error: Z-position”
at https://forums.creativecow.net/cgi-bin/new_read_post.cgi?forumid=2&postid=859101&theadid=859099&pview=t

Perhaps best then to go with the tutorial you had.
Could you post the url for the original tutorial, then I’ll have a go at rewriting the expression for 3D

[Filip Vandueren]

The tracking is not always calculated from the left, it depends on your paragraph alignment.
Setting the text to center would give the most predectable results IMO.

I had never used the Line Anchor property before, and I must say: it gives interesting results, allmost like parallax movement when you shift it around in combination with tracking.

[Filip Vandueren]

Yeah, that shoul do it.
just to be clear:

that has to be UN-checked.

[Filip Vandueren]

pre-comp and use it as a track matte, either an alpha or a luma matte, depending on what you want to achieve.

[Filip Vandueren]

The expression for thickness uses the value you have set as a starting point, so if you first set the thickness so it looks good when everything is at Z-depth=0, then apply the expression, it will scale proportionally after that.

I also noticed the error when one of the points is behind the camera, but didn’t know if it was an issue for your animation.
I’ll see if I can find the workaround for that.

[Filip Vandueren]

The expression for thickness uses the value you have set as a starting point, so if you first set the thickness so it looks good when everything is at Z-depth=0, then apply the expression, it will scale proportionally after that.

I also noticed the error when one of the points is behind the camera, but didn’t know if it was an issue for your animation.
I’ll see if I can find the workaround for that.

[Filip Vandueren]

Perhaps by using text on a spline with arrows from a dingbat font.
You can animate the First-Margin parameter to move them across the spline.

If you use an extra opacity animator, you can set the range to define howmany arrow-characters are visible.

[Filip Vandueren]

I sometimes use the Beam-effect on a non-3D solid:

Add a Beam effect
set the length to 100%
Give it this expression on Starting & Ending Point:

l=thisComp.layer("start or endlayer");
p=l.toComp(l.anchorPoint);

-> change the layer name in the first line to different layers for start and end-point

Adjust the colors, softness and thickness to taste.

If you want the thickness of the line to follow the correct 3D distortion add this expression to Starting and Ending Thickness:

l=thisComp.layer("start or endlayer");
w=length(l.toComp([0,0,0]), l.toComp([0,value,0]));

-> change the layer name in the first line to different layers for start and end-point

Put the layer with the lines in the back of the comp and it should look perfectly 3D, eventhough the lines are not.
If you need mulitple lines, you can duplicate the solid, or duplicate the Beam-effect, but select the option “composite on original” on all but the first beam.

[Filip Vandueren]

I sometimes use the Beam-effect on a non-3D solid:

Add a Beam effect
set the length to 100%
Give it this expression on Starting & Ending Point:

l=thisComp.layer("start or endlayer");
p=l.toComp(l.anchorPoint);

-> change the layer name in the first line to different layers for start and end-point

Adjust the colors, softness and thickness to taste.

If you want the thickness of the line to follow the correct 3D distortion add this expression to Starting and Ending Thickness:

l=thisComp.layer("start or endlayer");
w=length(l.toComp([0,0,0]), l.toComp([0,value,0]));

-> change the layer name in the first line to different layers for start and end-point

Put the layer with the lines in the back of the comp and it should look perfectly 3D, eventhough the lines are not.
If you need mulitple lines, you can duplicate the solid, or duplicate the Beam-effect, but select the option “composite on original” on all but the first beam.