Issue about Circle.ByBestFitThroughPoints

I have 10 lists of points, each has the same number of points. The order of the points of each list are the same in all the lists.

I creates Circle.ByBestFitThroughPoints for each list of points, the issue is the locations of start point of the circle are not the same.

For circles 0~2, 4~6, and 8~9 the start point of the circel are the same.

For circle 3 and 7, the start point of the circel are the same, but they are not the same as those in other circles.

Pic shows 10 cirles with different start point

  1. Why is the issue?
  2. How to solve it?

Not sure why you are seeing this, but try getting the point closest to the first point in your original list or another desired start point (Geometry.ClosestPointTo), finding what parameter that is on the uniform circle (Curve.PointAtParameter), multiplying that value by 360, and rotate each circle by that value about it’s center point using it’s normal as the axis of rotation.