How to cut a polygon with another one?

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3.50/5 (2 votes)

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C#

mathematics

Can someone help me?

I want to cut a polygon with another one...
Do you know an algorithm?

Thank you all.

Posted 9-Dec-10 9:09am

IDominator

Updated 9-Dec-10 9:26am

CPallini

v2

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CPallini 9-Dec-10 15:27pm

Could you be more specific? What do you really need?

AspDotNetDev 9-Dec-10 15:32pm

Do you mean cut out a portion of one polygon by overlaying another polygon on top of it and removing the section that overlaps? Would the result be the overlapping area, or would the result be the remainder of the first polygon (i.e., the portions of the first polygon that were not overlapped by the second)? And are we talking about simple polygons here, or are we talking about things like a square that is missing a small circular portion from its center (that would be a surface rather than just a polygon)?

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Albin Abel · Answer 1 · 2010-12-10T14:34:00

Hi,

I will give you a rough idea how it could be. By the way it is my own idea and not referring to any existing popular algorithm.

When take two polygons which intersects there are some node (point) must be inside the other polygon. So on a loop find the point inside using the point in polygon algorithm. So let us say a point inside a polygon and the next node is outside the polygon then it must be intersecting the vertex of another polygon. Find the intersection points and rearrange the point order to create the new intersected polygon. Hope this would helps. If you feel it make sense I will try to write some coding.