'Bisect Polylines draws lines bisecting the angle between vertices of a polyline. Length of bisector line is half the distance to the previous vertex in the vertex order of the polyline. Arc segments are treated as straight. Only new style 'lightweight' polylines are supported, not old style polylines.' Re: Angle bisector From the information you say you have, you should be able to create the arc using start-center-angle. However as you found, autocad wants to draw arcs in a counterclockwise direction.
Conditionally evaluates expressions
Supported Platforms: Windows and Mac OS
Signature
Type: Integer, Real, String, List, T, ads_name, or nil
Expression to be tested.
Type: Integer, Real, String, List, T, ads_name, or nil
Expression evaluated if testexpr is not nil.
Type: Integer, Real, String, List, T, ads_name, or nil
Expression evaluated if testexpr is nil.
Return Values
Type: Integer, Real, String, List, T, ads_name, or nil
The if function returns the value of the selected expression. If elseexpr is missing and testexpr is nil, then it returns nil.