AutoCAD Geometry (Autodesk.AutoCAD.Geometry)

Use this skill when working with geometric primitives - points, vectors, matrices, lines, arcs, curves, planes, and bounding boxes. These types are used throughout both AutoCAD and Civil 3D APIs.

Points

Point2d (struct)

Point2d p1 = new Point2d(100.0, 200.0);
Point2d p2 = new Point2d(300.0, 400.0);
double dist = p1.GetDistanceTo(p2);
Vector2d dir = p1.GetVectorTo(p2);
Point2d mid = p1 + dir * 0.5;   // midpoint via vector math
Point2d rotated = p1.RotateBy(Math.PI / 4, Point2d.Origin);

Point3d (struct)