Re: Corel draw 12 hpgl-plt file not true curves?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "jimmy2309a" <jimmy2309a@...>
wrote:

>
> I am by no means an expert but I do Some engraving and work with
> corel draw 9 for my engravings, HPGL has always out put straight
> lines for curves. HPGL-2 was supose to do true curves but I have not
> had any software that would read HPGL-2 files and work with my
> machines, The only thing I can think of is you may have a coarse
> output for your HPGL Files. With corel draw 9 when you save as PLT
> file I have a box that pops up for the plt output settings and under
> the Page Tab there is a Plotter units setting, the standered for HPGL
> output is something like 1016, this is how many line segments per 1"
> lines, if this is set to coarse or if you make your drawing to small
> for your final output you will see the line segments in the
> engraving. When I do My drawings i set the page size to the size of
> my plate I will be engraving so I don't have to scale the drawing
> after I export it. I don't know anything about corel 12 but it should
> have simular settings somewhere.
> I hope this helps some,
> Jimmy
>
>

Commercial interruption:

The problem with CorelDraw (any version after 9 up to 12 w/SP1
applied) is that the HPGL export filter is broken (uses course
segments for curves no matter what you pick in the output), and DXF
does not output curves either. Because Corel uses Bezier curves
(complex math curves with two points) the translation to curves that
have a start, end and radius (i.e. G-code G2 and G3) is not very easy.

To get true 4 node circles and complex arcs made from arc segments try
DXFTool

Free Demo at http://www.candcnc.com/DXFToolDetails.htm

NOTE: Only works with CorelDraw ver 12 and up because full VBA was
not supported in Corel prior to that.

It outputs good DXF files in a format most programs like SheetCAM can use.

Although primarily for Plasma cutting there are free CDR (Corel
format) artwork/clipart on the CandCNCSupport Yahoo Groups site in the
Files/Artwork section. Good for testing DXFTool.

Now back to your regular programming............

Tom Caudle
www.CandCNC.com