: How do I draw straight lines tangent or perpendicular to a path? The tangent is the line which is perpendicular to the local radius. Intuitively, it's the line "resting" or "balanced" on that

@Shelton719

For a straight line perpendicular to a straight line, rotate your line 90 degrees.

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@Nimeshi706

Using a free tool issued by "astute graphics" company. The free tools called SubScribe Free

this will install some useful tools in your illustrator toolbar, one of them called line tangent to two paths.



fly out this tool and you will see some other tools all are to make tangents and perpendiculars between lines and paths.



and as all astute graphics plugins it is very simple to use

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@Cugini998

There are quite many plugins that make this easy to do. Its even relatively easy to script.


Hotdoor CAD tools
Astute Graphics, have tools for this
Some scripts by Hiroyuki Sato might help also, here and here


In any case you may want to know how to do this manually. I often do as not all the computers i use have all the tools i have at my workstation. This is how you do it.


Insert a point to the curve where you want to be tangent.
With the tangents visible use line tool to snap the tangent point, and drag to the to the point on curve that you made.
(Optional) Scale this line up say to 400% or so.
(Optional, for normal) Rotate the tangent by 90 degrees centered on point:


With rotate tool, Alt + click on the point on curve
Type 90 degrees
Hit copy.





Timelapse 1: How to make a tangent line in AI (Scale step missing, sorry).

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@Hamaas979

Hold Shift to constraint. This works for lines keeping them 0, 45, 90, 180 etc. degrees. You can also keep scale and rotation proportional. Or when dragging objects. Good Luck.

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