STEP CAD interchange format

Plain text file format.
Based on EXPRESS language schema.
Deals with named objects rather than just raw geometric information.

Example: pump.stp

A triangular face might be represented as follows.

#2359144 = FACE_SURFACE('',(#2359150),#2359145,.T.);
#2359145 = PLANE('',#2359146);
#2359146 = AXIS2_PLACEMENT_3D('',#2359147,#2359148,#2359149);
#2359147 = CARTESIAN_POINT('',(6.525690078735,4.408679962158, -11.11690044403));
#2359148 = DIRECTION('',(0.238627661246,-0.89478112513,0.377390483981));
#2359149 = DIRECTION('',(-0.964060798003,-0.171531943693,0.202888072708));
#2359150 = FACE_OUTER_BOUND('',#2359151,.T.);
#2359151 = POLY_LOOP('',(#2359152,#2359153,#2359154));
#2359152 = CARTESIAN_POINT('',(6.525690078735,4.408679962158, -11.11690044403));
#2359153 = CARTESIAN_POINT('',(6.107540130615,4.334280014038, -11.02890014648));
#2359154 = CARTESIAN_POINT('',(6.103960037231,4.317719936371, -11.06589984893));