The general format of a $PP entry that controls the translation of geometric information from the drawing into NC code is as follows:
NC CODE # FORMAT ; SWITCHES = GEOMETRY
This format is identical in use to the text control lines in the previous section except that the codes will be output based on geometry instead of text statements.
The GEOMETRY portion of the $PP entry indicates that a specific value from the geometry in the drawing is to be formatted and output as NC code. The geometric entries that are predefined to the post include standard X,Y, and Z values as well as other computed values. These entries are set based on the piece of geometry that is being processed (line, point, arc).
For example, if the $PP file contains the entries "X#4.3=X" and "Y#4.3=Y", then any X or Y coordinates from the drawing will be output with a format of "4.3". When a line from 0,0 to 2.22222,3.333333 is processed by the post, the NC code "X2.222 Y3.333" will result. If "3.4" had been the format, then "X2.2222 Y3.3333" would result.
As another example, if the $PP file contains the entries "Z#4.3;-=X" and "X#4.3=Y and a line from 0,0 to 2.2,3.3 is processed by the post, the NC code "Z-2.2 X3.3" will be output.
Note that this example results in a transposition of axes, as well as a sign reversal of X coordinates that is necessary in some applications.