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Explanation of Offset algorithm


I have a small problem. I am trying to build my own cnc and implement offset algorithm, but i am not able to understand what "TIP", "FIP" mean. This seems so complicated! This is the link to description this algorithm: Here's a link I will be very grateful for your help!


Solution

  • The definitions reads: If the intersection point obtained by extended intersecting is on the line segment/arc, then the point is called a true intersection point (TIP). Otherwise, it is called a false intersection point (FIP).

    My interpretation is that a TIP is a point on a segment (line or arc) that intersects with another segment or an extension of it. A FIP is an intersection of two extended segments that does not lie on any of them.

    I agree with you, the definition is not clear (which is not good for a definition). Another interpretation (coming from the names rather than from the wording) would be that a TIP is the intersection of two segments and a FIP is the projected intersection of their extensions. My recommendation is to bear both interpretations in mind and keep reading until the definitions become clearer from their actual use.