On Thu, 2007-03-08 at 08:03 -0500, Dan McMahill wrote: [snip] > > IMO it would be a good practice to use the center of gravity as a > > mark/insertion point for pcb footprints/3D models. > > yes.
What do other packages with 3D modelling use for their models? Do you really mean centre of gravity, or some kind of geometric centre? (Thinking of modelling components with non-uniform material density). I'd have expected to use some centroid in the plane of the PCB, and to have the Z axis of the attach point on the component correspond to the plane of the PCB it rests on. Eg. SMDs would start at Z=0 and go upwards in Z the height of the component. A through-hole capacitor would have its base at just above Z=0 (clearance for lead expansion / contraction), have the cylinder extending up with +ve Z, and leads protruding down with -ve Z. (assuming we go so far as modelling leads). -- Peter Clifton Electrical Engineering Division, Engineering Department, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA Tel: +44 (0)7729 980173 - (No signal in the lab!) _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
