Hi Peter, > What do other packages with 3D modelling use for their models?
I don't know, ... yet. > Do you really mean centre of gravity, or some kind of geometric centre? > (Thinking of modelling components with non-uniform material density). Well, erm, you're right, center of gravity isn't exactly the right description. > 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). I used the conventions you described as a matter of fact. And I did model the leads in the parts I have sofar. For most parts I have a model with leads with the full length as specified in the datasheet, and a model with cut-off leads for through hole parts protruding through the pcb for about 1.0 mm. Sofar I have some 500+ models in AutoCAD (and SAT file format) which I use for mechanical designs. Kind regards, Bert Timmerman. _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
