Re: Cad File Formats (was programing a DRO)

Matt,

If you want to write file to G code converter, you may want to look at using
a .PLT file.

I am getting ready to write a VBA program for AlphaCam using a .plt file as
the input.

A lot of users use Corel Draw for their artistic drawings. The .plt file
output is just a bunch of small straight lines. The pen up (PU) command
would be your rapid move G0. The PD commands would be your G01 moves.

Now what you may want to do If you are using VB is to look at the data and
see if you could convert any of the series of straight lines into curves or
circles.

The next thing that you will need to do is to display the drawing in VB and
move the drawing to a new 0,0 point. From what I have seen in Corel, the
center of the page is their 0,0 point.

Once you get everything into a series of vectors, you can apply a radius
(cutter) offset. You could also let the user choose the number of passes
that they want to cut through the material.

Bob Campbell

----- Original Message -----
From: Randolph Lee <boss@...>
To: <CAD_CAM_EDM_DRO@onelist.com>
Sent: Wednesday, July 07, 1999 12:42 PM
Subject: [CAD_CAM_EDM_DRO] Cad File Formats (was programing a DRO)


> From: Randolph Lee <boss@...>
>
> Matt, The concept of .dxf as the universal format must have the folks
> at autoDesk laughing their heads off as they have changed it with
> ever release... and if you add in about 50 or 100 other flavors of
> .dxf floating around... well it's a bit of a mess really.
>
> I have had the best luck in getting files in and out of the ashlar
> velum solids99 program I use to be the .Sat format but that is for
> 3d and only for software that uses ACIS.
>
> Sat is for exchange of 3d files between software that uses the ACIS
> shell from Spatial tech (over 200 applications and 1.5 million users
> at last count) to date I have used .sat files from Autocad , Ironcad
> , FromZ , and Turbo Cad with no problems... if any here use an ACIS
> enabled Cad/Cam program I would enjoy sending them a few files to
> test this going the other way
>
> That is not the case with .dxf or .dwg or .igs... and if I ever do
> make the move to real CAM this is the current list of acis based Cam
> software. I should be able find something in this list..
> Http://www.spatial.com/action/applications.htm
>
> I did not buy my copy of Velum Solids99 I got it as a bonus in
> addition to some contract development work I did for Ashlar... but
> even at $3,000 a seat I think It's good value ...
>
> (If any windows users want to look at the demo version on the Ashlar
> site Http:/www.ashlar.com (call them to ask for a demo CD rom)
> they should know that until the Mac version is changed from QD3d to
> OpenGL the Windows and NT versions of it are actually slightly
> faster; on a SGI 450 under NT vrs my B&W 350 the SGI will do final
> ray traced renders about 10% to 15% quicker right now) so until the
> fall, the fastest implementation of VS99 is on a high end NT
> workstation (on operations that don't use Open GL like rendering to a
> file the B&W Mac 350 is about 5% faster than the SGI 450 right now)
>
> ... in a few weeks i will have some examples of Model engineer sorts
> of things I have done with it up on my web page... I am doing a
> Virtual version of the Stuart Steam hammer before I start cutting
> metal... I model the casting as a solid than 'machine it on the
> screen" then select it and have VS99 create a 4 view drawing sheet
> with sections a "B" sized 11x17 sheet for each part... I have it
> about 1/2 done and when finished I will use it to make an animated
> version that I will post on my page...
>
> another format that might be useful to the list as a conversion base
> is the .stl format used for stereo lithography... it's main problem
> is it's very very wordy... Here is a .stl file for a 1 inch plain
> cube it is about 2 k long... if I round over the the the 4 edges of
> the top face with .050 radius the file grows to 137k! (be glad to
> send it to any one who is interested... ) complex .stl files are Huge
> but they are simple... and might be amenable to simple parsing into
> Cam file formats... are there any Solid litho experts on the list
> yet?
> solid ascii
> facet normal 0.000000 0.000000 1.000000
> outer loop
> vertex 1.000000 1.000000 1.000000
> vertex 0.000000 1.000000 1.000000
> vertex 1.000000 0.000000 1.000000
> endloop
> endfacet
> facet normal 0.000000 0.000000 1.000000
> outer loop
> vertex 1.000000 0.000000 1.000000
> vertex 0.000000 1.000000 1.000000
> vertex 0.000000 0.000000 1.000000
> endloop
> endfacet
> facet normal 0.000000 0.000000 -1.000000
> outer loop
> vertex 1.000000 0.000000 0.000000
> vertex 0.000000 0.000000 0.000000
> vertex 1.000000 1.000000 0.000000
> endloop
> endfacet
> facet normal 0.000000 0.000000 -1.000000
> outer loop
> vertex 1.000000 1.000000 0.000000
> vertex 0.000000 0.000000 0.000000
> vertex 0.000000 1.000000 0.000000
> endloop
> endfacet
> facet normal 0.000000 -1.000000 0.000000
> outer loop
> vertex 0.000000 0.000000 1.000000
> vertex 0.000000 0.000000 0.000000
> vertex 1.000000 0.000000 1.000000
> endloop
> endfacet
> facet normal 0.000000 -1.000000 0.000000
> outer loop
> vertex 1.000000 0.000000 1.000000
> vertex 0.000000 0.000000 0.000000
> vertex 1.000000 0.000000 0.000000
> endloop
> endfacet
> facet normal -1.000000 0.000000 0.000000
> outer loop
> vertex 0.000000 1.000000 1.000000
> vertex 0.000000 1.000000 0.000000
> vertex 0.000000 0.000000 1.000000
> endloop
> endfacet
> facet normal -1.000000 0.000000 0.000000
> outer loop
> vertex 0.000000 0.000000 1.000000
> vertex 0.000000 1.000000 0.000000
> vertex 0.000000 0.000000 0.000000
> endloop
> endfacet
> facet normal 0.000000 1.000000 0.000000
> outer loop
> vertex 1.000000 1.000000 1.000000
> vertex 1.000000 1.000000 0.000000
> vertex 0.000000 1.000000 1.000000
> endloop
> endfacet
> facet normal 0.000000 1.000000 0.000000
> outer loop
> vertex 0.000000 1.000000 1.000000
> vertex 1.000000 1.000000 0.000000
> vertex 0.000000 1.000000 0.000000
> endloop
> endfacet
> facet normal 1.000000 0.000000 0.000000
> outer loop
> vertex 1.000000 0.000000 1.000000
> vertex 1.000000 0.000000 0.000000
> vertex 1.000000 1.000000 1.000000
> endloop
> endfacet
> facet normal 1.000000 0.000000 0.000000
> outer loop
> vertex 1.000000 1.000000 1.000000
> vertex 1.000000 0.000000 0.000000
> vertex 1.000000 1.000000 0.000000
> endloop
> endfacet
> end solid
>
>
>
> >From: "Matt Shaver" <mshaver@...>
> >
> > > From: <blinda@...>
> > >
> > > I wrote a program
> > > to read the dxf file and produce the m and g codes for my machine.
The
> > > program is simple minded but works pretty well for my purposes. I had
> > > planned to make several improvements before offering it for use by
others
> > > but I'm not not optimistic I'll do that now. If you or anyone else on
> > > the list are interested I can make it available.
> >
> >I'd be interested in seeing this, manly as a tutorial on the innards of
.DXF
> >file structure! I'm wondering if .DXF is consistent between Cad programs,
or
> >if their is a core set of entities and functions that everyone supports
plus
> >a bunch of platform specific garbage that would need filtering out. It
looks
> >like .DXF is going to stay THE data interchange standard for CAD data in
the
> >real world, although I had high hopes for VRML taking over this role at
one
> >time. IGES was also a promising standard before it went "Hollywood" as
STEP.
> >See this site for the last public definition of this once useful
standard:
> >
> >http://www.iges5x.org/
>
> Randolph Lee boss@...
> ---------------------------------------------------------
> Windshadow Engineering Nantucket Island, MA USA
> ---------------------------------------------------------
>
> --------------------------- ONElist Sponsor ----------------------------
>
> Attention ONElist list owners.
> http://www.onelist.com
> We've just added a "NO ATTACHMENTS" option. See homepage for details.
>
> ------------------------------------------------------------------------
> Welcome to CAD_CAM_EDM_DRO@...,an unmodulated list for the
discussion of shop built systems in the above catagories.
> To Unsubscribe, read archives, change to or from digest.
> Go to: http://www.onelist.com/isregistered.cgi
> Log on, and you will go to Member Center, and you can make changes there.
> bill,
> List Manager
>