Re: How to retrieve startAngle and endAngle of Arc object

Dear Nam,

AngleTo returns the shortest possible non-negative angle, measuring in whatever 3D plane gives the smallest angle.

This angle will always be positive (or zero).

If you want to obtain a negative angle, you need to specify a plane in space to force the measurement to go in one specific direction.

This can be achieved using the AngleOnPlaneTo method:

http://www.revitapidocs.com/2018.1/417e2c71-f806-746c-c638-d54d220f8476.htm

Please always study the Revit API documentation carefully before asking too many questions.

Thank you!

Cheers,

Jeremy