/*! \page create_3dsketcher_page 3D Sketcher 3D Sketcher allows creating a closed or unclosed 3D wire, made of consequent straight segments. Example: \image html 3dsketch4.png To create a 3D Sketch, select in the main menu New Entity -> Basic -> 3D Sketch. \image html 3dsketch_dlg.png The first point of a sketch can be defined by \b Absolute coordinates X, Y and Z. After this, it is possible to add straight segments. Each segment starts at the end point of the previous segment or at the first point of the sketch, if there are no validated segments. The second point of a segment can be defined in two different ways depending on the selected Coordinates Type radio buttons: By Cartesian coordinates , which can be either: - \b Absolute coordinates \b X, \b Y and \b Z, or - \b Relative coordinates \b DX, \b DY and \b DZ with respect to the previous applied point, By Angular coordinates, which include: - the \b Length of the segment and an \b Angle in the chosen plane (OXY for example) in \b Relative mode. The angle is then relative to a local coordinate system with the last point of the sketch as origin. \image html 3dsketch_angle_rel.png - the \b Radius (i.e. the distance from the origin) and an \b Angle in the chosen plane in \b Absolute mode \image html 3dsketch_angle_abs.png In both angular modes you can additionally specify the following: - the second \b Angle (latitude) \image html 3dsketch_2angles_rel.png - the \b Height \image html 3dsketch_angle_height_rel.png To validate a segment and to proceed with the definition of the next one, click Apply button. \b Undo and \b Redo buttons, respectively, remove or restore the last segment in the wire. \n Sketch Validation button applies the wire, built by the user, "as is". \n Sketch Closure closes the Sketch by a straight line from the start to the end point and applies it.