O is the datum, P the feature dimensioned and AXIS either 'x' or 'y', the coordinate stated. The dimension is a leader from P to the point L and the distance at its end, with no dimension line and no arrow. An 'x' ordinate’s leader runs up or down the sheet and a 'y' ordinate’s across it, so L must lie away from P in that direction; where L is off the line through P, the leader jogs across in its middle third.

A part dimensioned this way gives every feature its distance from one datum, usually a corner, as a column of x values along one edge and a row of y values along the other. A machinist or a program reads each position straight off the datum, and no error adds up along a chain of dimensions.

The label is the distance, without sign, to a micron, measured when the drawing is lowered, so it follows the geometry; LABEL gives literal text instead.

 ## A plate with two holes, dimensioned from its lower left corner
 D = draw.Drawing ();
 D = D.polyline (geom.Polyline ([0, 0; 80, 0; 80, 50; 0, 50], ...
                                'Closed', true));
 D = D.circle ([20, 15], 4).circle ([60, 35], 4);
 D = D.ordinate ([0, 0], [20, 15], 'x', [20, -10]);
 D = D.ordinate ([0, 0], [60, 35], 'x', [60, -10]);
 D = D.ordinate ([0, 0], [20, 15], 'y', [-10, 15]);
 D = D.ordinate ([0, 0], [60, 35], 'y', [-10, 35]);

See also: dim, leader

Source Code: draw.Drawing