Multiple UI drawn circles, how to cut out any of the overlapping circles?

Questions & Answers
1

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So, in our RTS each unit or building has strategic circles. If you have multiple units or buildings selected it looks like the picture to the left. I want to make it look like the picture to the right, where anything inside the outer edges of their circles is no longer shown.

I draw these using vectrosity, mentioning this just in case vectrosity provides a way of doing this, or can be modified to do this.

How would I go about “merging” or just culling the circles inside of their total area?

2

Create object “circle” which contain points. And drawing circle like line.

Create list of circles.

Check all points in all circles for rule “is point containing in other circles” if yes then delete this point from circle.