United3dArtists Archive

Ideally, I'd like to be able to take a single polygon, of any number of sides, laying flat on the grid, and export it to an HPGL/1 PLT file. (Not, NOT, in no way, HPGL/2.)

HPGL/1 PLT files are ordinary ASCII text files.

Why this format? Because I need a NON-TRIANGULATED vector format and HPGL/1 is relatively simple and very well documented. It's also very simple to print to an output device such as an old Hewlett Packard pen plotter.

Just make a batch file like so...

MODE COM1: 9600,N, 8,1,P
pause
copy /b %1 COM1

Name it plot.bat and toss it in a folder with the plt files and use it thus;

c:\pltfiles\plot drawing.plt

The pause is so the user can verify the port mode setting worked. Ain't that nifty? Printing in windows XP, without any print driver required! I bet this would work with older parallel port laser printers that have the HPGL/1 language.

It would also be nice to be able to import HPGL/1 files into trueSpace. Building a 3D object directly from a multi-view drawing would be useful to me.

Back in the early days of CAD, mailing plt files on disks was one way to send plans and drawings, and the recipient didn't need anything but a DOS PC and a compatible plotter to print them. Much cheaper postage than sending prints in large envelopes or rolled up in tubes, and the recipient could cheaply make as many copies as needed.

What I want to do is make some cutting patterns to use with a bandsaw, for making a master frame pattern for my Space Battleship Yamato pistol. My IBM 7371 (an HP 7470A in disguise) cost me a whole dollar and I have a bag full of red pens i got for free. Can't print any cheaper than that!

I can easily make the polygons for the outlines from my 3D model. The problem comes from all the non .cob export formats tS 6.6 outputs being triangulated, and no way I've found to convert any of them to HPGL/1 format. May be some other format that'll work in Conversion Pack 2.1, but I don't have that and of course there's no way to get it now.

Maybe you could use one of the free cad programs like from http://www.cadstd.com/" to read the triangulated dxf from trueSpace and clean up the triangles. I've never done anything like that so it's just an idea.

The free version of that CAD program doesn't do HPGL.

I have found a roundabout method.

1. Prepare the scene by creating the shapes to be converted.
2. Switch to top view and arrange the shapes to fit into an area matching the width:height ratio of the paper you'll be plotting to.
3. Set the background to black and render mode to wireframe.
4. Render to bitmap, at least 2048x1536.
5. Download and install the Raster to Vector converter from http://www.raster-vector.com" The demo converts up to three files per session, no other limits, no buggering up the output with watermarks etc.
6. Set the output format to HPGL. Also set the output location and under Options, set the scale.
7. For output to US Letter, 10 works well if the original bitmap is 1024x768. Doubling the original to 2048x1536 and halving the scale to 5 produces a plot exactly the same size, but with smoother and more accurate lines.
8. Send it to the plotter using the batch file in the first post of this thread.