使用 NetDxf for c# 检索圆弧的起点和终点

Question

I need to retrieve the start and end point of an Arc entity using NetDxf to analyze my .Dxf file. So far i was only able to retrieve the center and the angle of the arc. Is there a way to retrieve the start and the end point using NetDxf library for c#?

Answer 1

In a DXF file, an arc is defined by the following properties:

• Center (DXF 10)
• Radius (DXF 40)
• Start Angle (DXF 50)
• End Angle (DXF 51)

Where the start/end angles are always measured counter-clockwise from the x-axis of the object-coordinate-system (OCS) plane in which the arc resides.

From these properties, you can easily obtain the start & end points by calculating points at an angle equal to either the start or end angle from the center point, at a distance equal to the radius, ie:

Start Point = Center + (Radius*cos(StartAngle), Radius*sin(StartAngle))