How to find contact lines on forms?

Question

JavaScript

Hello everyone, I don’t know how to explain exactly, I need to find the lines of contact with the forms.

There are two forms, you need to find the red lines as in the picture, something like draw a belt around the gears))
Find the option with the help of rays, start from some point and find the contact lines, like here https://www.redblobgames.com/ articles/visibility/ but I don't think this is the best option.
Any idea how this can be done?

Answer 1

There is a similar method, but not by means of rays, but by constructing a convex geometry. Lines can be drawn from it. This method is called Convex hull
https://github.com/mikolalysenko/monotone-convex-h...

Answer 2

Look for the term "junction points" - it's from geometry, possibly from descriptive geometry. Then you will understand how to do it.

Answer 3

connect each point of the first figure with all points of the second and choose from the resulting lines those that do not intersect any other lines