re: HPGL vs. Gcode was Compucut ?
Posted by
Alan Marconett KM6VV
on 2000-12-30 10:08:27 UTC
Ballendo,
Looks like you're of the same opinion I am! My first thoughts were to
use HPGL for just the reasons you mention. That was before I knew about
gcode. I'd still like to convert HPGL into .DXF or gcode so that I can
import some PCB designs and old drawings. And yes, I have had an HP
7475A plotter for a LONG time!
I've got linear interpolation working on my controller (on "paper", no
step/dir hardware yet), and also circular interp. written. Circular is
not correct yet. several test vectors are working, but some of the most
obvious "edge tests" don't! More work required. I wasn't going to
bother with the 4-phase, leaving that for just the jog controllers, but
I may go ahead and re-write the 4-phase to run 3 axis. That would allow
me to test a little further, actually RUN some hardware!
Happy Holidays to you and your family.
Alan KM6VV
ballendo@... wrote:
Looks like you're of the same opinion I am! My first thoughts were to
use HPGL for just the reasons you mention. That was before I knew about
gcode. I'd still like to convert HPGL into .DXF or gcode so that I can
import some PCB designs and old drawings. And yes, I have had an HP
7475A plotter for a LONG time!
I've got linear interpolation working on my controller (on "paper", no
step/dir hardware yet), and also circular interp. written. Circular is
not correct yet. several test vectors are working, but some of the most
obvious "edge tests" don't! More work required. I wasn't going to
bother with the 4-phase, leaving that for just the jog controllers, but
I may go ahead and re-write the 4-phase to run 3 axis. That would allow
me to test a little further, actually RUN some hardware!
Happy Holidays to you and your family.
Alan KM6VV
ballendo@... wrote:
><SNIP>
> Rab wrote:
> >Could anyone explain the advantages of G-Code over HPGL ?
> >My current machine, a Roland uses HPGL to cut in 3D very
> >successfully, although I have nothing to compare it with, it
> >contours well enough for me. It seems that compucut would work
> >similarly ?
>
> >I don't understand the unipolar v. bipolar thing yet, is there a big
> >difference ?
>
> Rab,
>
> HPGL (Hewlett Packard Graphics Language) was designed by HP as a
> language to drive vector plotters to output computer drafted images.
> It is a 2D language BY DESIGN. The SP (select Pen) is often used
> to 'select' height in CNC programs which input HPGL. This usage makes
> it a 2-1/2D Language. The third axis 'height' can be 'selected', much
> as a pen "would have been" selected, so the drawing would be made in
> differing colors.
>
> There have been many attempts over the years by many manufacturers,
> to expand HPGL to 3D. This is/was largely due to the fact that nearly
> EVERY drafting program had a standard HPGL output implemented(usually
> the HP7475 'flavor'). This was at a time when many other drafting
> exchange standards (IGES, DXF,etc.) were either poorly implemented,
> poorly defined, or evolving.