/// <summary>
/// Constructs a new AKT_Line segment from start point, direction and length.
/// </summary>
/// <param name="start">Start point of AKT_Line segment.</param>
/// <param name="direction">Direction of AKT_Line segment.</param>
/// <param name="length">Length of AKT_Line segment.</param>
public AKT_Line(AKT_Point3d start, AKT_Vector3d direction, double length)
{
AKT_Vector3d vector3d = direction;
if (!vector3d.Unitize())
{
vector3d = new AKT_Vector3d(0, 0, 1);
}
this.m_from = start;
this.m_to = start + (vector3d * length);
}
/// <summary>
/// Gets the unit tangent vector along the AKT_PolyLine at the given parameter.
/// The integer part of the parameter indicates the index of the segment.
/// </summary>
/// <param name="t">AKT_PolyLine parameter.</param>
/// <returns>The tangent along the AKT_PolyLine at t.</returns>
public AKT_Vector3d TangentAt(double t)
{
int count = this.points.Count();
if (count < 2)
{
return(AKT_Vector3d.Zero);
}
int num = (int)Math.Floor(t);
if (num < 0)
{
num = 0;
}
else if (num > count - 2)
{
num = count - 2;
}
AKT_Vector3d mItems = this.points[num + 1] - this.points[num];
mItems.Unitize();
return(mItems);
}