PointOnFace.cs

/// <summary>
        /// Return an arbitrary point on a planar planarFace,
        /// namely the midpoint of the first mesh triangle.
        /// </summary>
        /// <returns name="point"></returns>
        public static XYZ PointOnFace(PlanarFace planarFace)
        {
            XYZ point = new XYZ(0, 0, 0);
            Mesh mesh = planarFace.Triangulate();

            for (int i = 0; i < mesh.NumTriangles;)
            {
                MeshTriangle triangle = mesh.get_Triangle(i);
                point += triangle.get_Vertex(0);
                point += triangle.get_Vertex(1);
                point += triangle.get_Vertex(2);
                point *= 0.3333333333333333;
                break;
            }
            return point;
        }