On 06/22/2011 01:34 AM, Lorenzo Marcantonio wrote: > On Wed, 22 Jun 2011, Vladimir Uryvaev wrote: > >> As I see, there's no more (or very little) activity on this task. >> >> I developed the approach on how to convert KiCAD to metric unit. This >> approach >> is fully based on OOP. >> >> There are several stages on converting: > CUT > > I completely disagree. This is too complex for what we want... in fact > OOP most of the time only complicates life but that's IMHO:P > > In the past the best way do defeat the issue was agreed to be the common > divider, something like 200nm or such. Just use it instead of the > current decimil and fix the scaling factors in the conversions (which > are mostly in the common/ code). Voilà, metric kicad with no rounding > issues...
I still agree with Lorenzo, Alex, and the factors that led to this posting back here: https://blueprints.launchpad.net/kicad/+spec/unit-system which I personally asked Alex to do, just to get it documented. Simply changing the internal unit to a new fixed quantum is the best path in my opinion. From there you only need 2 scaling factors to generate mils or your most preferred metric unit. Vladimir, I don't know if you are proposing working with alternate sets of internal units. If so, I think that is unnecessary and probably a difficult path. > But IMHO it should be done *together* with the new file format so to > have only one format conversion to do... i.e. traditional kicad in > decimils and SWEET/sexp/whatever in nano units... Regarding the file format issue, I see no reason why the current file formats cannot be tweaked to support metric or imperial. So I disagree with Lorenzo on this. No reason to wait. I see a need for only two units in the file PCB formats: 1) Imperial. The blueprint says 1/100th of a mil. But I would argue adding a decimal point to the numbers, and simply saving them as mils in files. I do not think we'd have to use exponents, simply numbers with decimal points. Such as 70.378 (mils). Exponents are not desirable. (See below for why a decimal point is helpful in the files.) 2) Metric. Somebody pick, if a decimal point is used in the number, it can even be millimeters. Each PCB file type can name which of the two units it is using (with perhaps a third being what we have now). On file loading, these numbers can be converted to the 1 nanometer internal unit without error or any rounding, exactly. On file saving, things are a little different. Because you have such fine granularity in the 1 nm internal unit, converting to say 1/100th of a mil *whole number* cannot be done without some rounding. To avoid the rounding on the conversion in this direction, we can use a decimal point in the numbers saved within the PCB files. If this is done, then I see no problems with my plan, somewhat modified from the blueprint. Dick _______________________________________________ Mailing list: https://launchpad.net/~kicad-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~kicad-developers More help : https://help.launchpad.net/ListHelp
