Mason uses a number of "Smart Footprints", basically components which use the dynamic (primitive) component format.
Parts such as microstrip or stripline include both an electrical and a physical description. These are examples of parts with dynamic footprints, and since Mason knows both the devices's dimensions and how these parts connect to each other these can automatically be laid out.
Another class of "Smart Footprint" are parts with the layout defined but the electrical properties are linked to a Touchstone (S2P) file. Some common footprints (e.g., 0201, 0402, 0603, 0805, 1206, and 2010) can be found in the "lumped_elements" library. Mason assumes the parts get connected at the mid-point (the center of the pad). If these components are used, care must be taken to keep the microstrip layout consistent on both sides of the Smart Footprints. For example, for a Wilkinson where the microstrip lines touch the resistor on both sides, calculations must be performed to make sure that the distance left by the microstrips equals the distance between the center points of the resistor's footprint. Make sure no offsets in the microstrip are created (leaving the microstrip fractionally open).
To use the smart footprint, the Package should be something like "file: microstrip/mline.xml" (using a microstrip line) or "file: lumped_elements\0402.xml" (using a Smart 0402 footprint).
Mason can also use dumb footprints, but the output to the Layout ASC file will not automatically place these. A human must manually place these parts... this may be safer for some layouts.
Copyright 2010, Gregory Kiesel