/*! \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. When the first point is defined, it is possible to add straight segments. Each segment will start at the end point of the previous segment or at the first point of the sketch, if there are no validated segments. The way of segment construction can be selected by the Coordinates Type radio buttons. 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. A segment can be defined by: - Cartesian coordinates of its second end, which can be either: - \b Absolute coordinates X, Y and Z, or - \b Relative coordinates DX, DY and DZ with respect to the previous applied point, - Angular coordinates of its second end specified by: