How do you manage to split a polygon (flowchart)

[Majid Hojati]

Hi,
This question is not related into this project, I would thank you if you halp me,
I have a polygon, I want to split it into three equile parts, I have a senario as bellow,
1- user must select a vertex on polygon
2- user must add direction to start split on
3- based on the node and direction we must select a line segment on polygon
4-??????

I have no idea how to go farther and then do what to split that line segment.In fact here there is some problems,
1- how we can find if the line segment is devidable into for example 3 parts?how we van determine the lenght of each segments on line to divide?
2- if line segment changes its direction what will happen?

Can some one give me some hints how to reach a flowchart on his?
thanks

[FObermaier]

I don't understand what you are trying to achieve. Maybe an image will help.

[Majid Hojati]

Hi,

In fact in above image I want to split two polygons, I have called them 1 and 2,

I want to devide polygon number 1 into 3 parts. I know which edge have to divided. I have lenthes on it, 5m,10m and 2m,How can I manage to do it, I can get this edge easily. this is even harder when we deal with edges that have segments (as I show in polygon 2), In polygon 2 the edge has two segments. Here I dont know how I find that the second segment of edge is in direction of the first one and It is split able or it is not,

I searched and found that some people talk about area, we must first calculate area and then try to find best matching lenghes on edges. 

Do you have any idea which gives me hints how to do it. I want a general algorithm that is able to deal with all kind of polygons.