About this 3D model

**There's a greatly improved version: "Customizable Hith Joint (CSG version) (library)"** http://www.thingiverse.com/thing:397553 . This is a trapezoidal Hirt-Joint generator. usage: * either use customizer * or use it as a library: hirth(   period_number,   flank_angle,   base_hight,   vertex_radius,   [cutround_diameter|default=0...do_not_cut_round],   [bore_radius|default=0...no_bore],   [vertical_stretching_factor|default=1],   [colormarked_vertices|default=false]); note: vertical stretching changes flank angle finishing & publishing motivated by: http://www.thingiverse.com/thing:370976