Re: center - here are some relevant script properties and functions that were added a while ago in V4. These can be called on a curve or a curve segment:

crv.isPlanar - Property that returns true if the curve's control polygon is planar.

crv.planarFrame - Property that returns a coordinate frame with an origin point at the curve's control polygon centroid and a z axis along the plane normal, only valid if crv.isPlanar == true.

crv.isOnPlane( frame ) - Function that returns true if the curve is on the given frame's x/y plane.

crv.isOnParallelPlane( frame ) - Function that returns true if the curve is on a plane parallel to the given frame's x/y plane.

crv.isClosed - Property that returns true if the curve is closed.

crv.isPeriodic - Property that returns true if the curve has periodic ends (overlapping control points at start/end rather than a corner point at the start/end).

crv.isDegenerate - Property that returns true if the curve has a degenerate control polygon with all the points stacked in the same spot.

crv.isLine - Property that returns true if the curve has the shape of a line.

crv.isSimpleLine - Property that returns true if the curve is a simple line segment made up of only 2 control points.

crv.isCircle - Property that returns true if the curve is a circle.

crv.isArc - Property that returns true if the curve is a circular arc.

crv.isEllipse - Property that returns true if the curve is an ellipse (either a full ellipse or an elliptical arc).

crv.conicFrame - Property that returns the coordinate frame of a circle, arc, or ellipse. Only valid if isCircle, isArc, or isEllipse returns true.

crv.conicRadius - Property that returns the radius of a circle, arc or the x-axis radius of an ellipse. Only valid if isCircle, isArc, or isEllipse returns true.

crv.conicRadiusY - Property that returns the y-axis radius of an ellipse. Only valid if isEllipse returns true.

crv.conicEndAngleRadians - Property that returns the end angle in radians of a circular arc. The arc starts at the x-axis of the arc's frame. Only valid if isArc returns true.


- Michael