thanks very much, brian. the extra arc codes in my example were possibly because i took an existing gerber and kept deleting stuff in a text editor and loading back into gerbview, repeatedly, until i thought i had a reasonable example.
hwn --- In [email protected], Brian Sidebotham <brian.sidebot...@...> wrote: > > 2009/5/8 Brian Sidebotham <brian.sidebot...@...>: > > 2009/5/8 bears1bear <h...@...>: > >> with my first message i provided gerber code that caused > >> gerbview to evidence the problem. > >> figured i'd not clog up the works with more such until/unless > >> requested by somebody planning to actually look at the > >> problem. > >> > >> these files, btw, are not sourced from the kicad tools, as i'm > >> just doing some quick gerber based layout reviews. > >> (i suspect that gerbers generated from within kicad have had > >> such problems ironed out long ago.) > >> > >> kindly advise if i should provide an additional file. > >> thanks, > >> hwn > > I have tested your file, and seen the problems. I have also written a > much easier example to demonstrate the problem with gerbview which you > can find at the end of this mail. On the surface the problem appears > to be with GerbView's interpretation of the G02 and G03 (circular > interpolation) commands. It seems to be getting the clockwise and > c-clockwise directions wrong. > > Note that in order to draw the arc, the G02 command should be being > used to interpolate clockwise (in my example below), but instead G03 > gives the correct result. I will investigate the code. The problem is, > I would expect changing the code to G02 to give a 270deg arc proving > the error, but instead it seems to give a 360deg arc. I will file a > bug report on bugzilla with the simplified gerber below to highlight > the problem. I will investigate the code for gerbview and see what I > come up with. > > Interestingly KiCad does not plot using G02 and G03 commands, it > instead draws lots of small linear lines to create arcs. I never > realised this before investigating this problem. > > Best Regards, > > Brian. > > --- > > G04 Set Units to inches* > G70* > > G04 Turn 360degree on* > G75* > > G04 Set Pen at 0,0* > G01X0Y0D02* > > G04 Set Absolute Coords* > G90* > > G04 Draw 2in Box* > G01X1000Y1000D02* > Y-1000D01* > X-1000D01* > Y1000D01* > X1000D01* > > G04 Draw 1in Rad Arc, Clockwise 90Deg - Note Should be G02 NOT G03!* > G01X-1000Y0D02* > G03X0Y1000I1000J0D01* > > M02* >
