What vendor part number would you use for each of your different resistor values?

While the symbol and the footprint for a 1k 1% 0805 resistor is the same as for a 10k 1% 0805 resistor, the vendor part numbers are not the same.

So while one could easily add a part-number field to the component (the PCAD term for a combined symbol + footprint), and modify that as needed in the same way one modifies the part value (i.e., every time you place a resistor on the schematic), vendor part numbers for resistors (and caps and other things) aren't simple (usually) so having a different component for each value (with a different vendor p/n) can be helpful.

I used to think this was silly, too, but it does simplify downstream processing by purchasing (making sure the right parts are ordered) and production (making sure the right values are in the right bin). Also, some companies have approved parts lists, even for passives, and the part numbers may be some company-special number. In many cases, engineers and layout people are not allowed to add parts to the library or modify part values.

I suppose that for my personal projects, this level of detail probably borders (or crosses right over) the line into anal retentive, but it's really nice when the BOM includes an orderable part number. It's one less thing to screw up when buying parts.

-a