to DeskProto home page
Contact  
looking glass icon
to DeskProto Facebook page
to DeskProto Google Plus page
to DeskProto Youtube page

Forum menu:

DeskProto user forum

Forum: communicate with other users.


Forum home page main
Forum:
Thread:
Best method for 2D DXF
You’re logged in as:guest
Online users:0
Online guests:138
 

page 1 of 3


Clinton
2007-04-02
15:40 CEST
Can anyone tell me the best method for generating 2D dxf especially for engraving fonts etc.

Some high end CAD programs seem fine for 3D but when trying to export 2D, it seems very hit and miss as to what in understood by Deskproto.

Thanks.

Lex
2007-04-03
09:55 CEST
Hi Clinton,

For me Rhino works fine: any font can be used, and when exporting to DXF you can choose how. Also offset lines (needed for the cutter radius correction) are easy. Rhino 4 should even be better as also hatching is possible, to create parallel 2D toolpaths.
Create the text as curves, and when exporting to DXF select Export curves as polylines.

Note that the 2D sample DXF files with the DeskProto logo have been made in an engraving program (www.galaad.net). Rhino 3 could not make the smooth offset lines to clear the inside of the font. Hatching is an alternative.

Of course I am very interested to hear about experiences with other drawing programs.

Lex.

Clinton
2007-04-03
12:03 CEST
Hi Lex

I have tried Maya (PLE), Vectorworks, TurboCad and must say Maya is assume for 3D but does not do 2D at all. The one key thing when exporting DXF from Maya is to "modify->delete by history" before exporting or you get all pollygons used to create your shape in the export. Both Vectorworks and Turbocad are clunky after using Maya.
Anyway it would be nice to settle on on application that does all.

I must say I find this DXF thing quiet confusing, for instance if I have a 3D model and define 2D points (or locus) for drill points, the 2D information is not loaded with the same offset as the 3D data. I would have thought 2D would be relative to XY and 3D would be relative to XYZ, obviously I don't understand DXF format :)

Lex
2007-04-04
08:47 CEST
Hi Clinton,

The different offsets for 2D and 3D DXF files in DeskProto are not caused by the DXF format or by not understanding this format. The difference is how DeskProto uses the information:
- 3D information is transformed according the the Part parameters that were set: rotation, scale, translation, etc. The input is the geometry in CAD coordinates, the output are toolpaths in machine-coordinates.
- For 2D this is not possible (for instance after rotating round the X axis, 2D would no longer have a constant Z level), so 2D files are interpreted in machine coordinates. For scaling and shifting in 2D the 2D Operation has it's own parameters.

The misalignment between 2D and 3D most probably is caused by the automatic translation that is applied by DeskProto. When in the Part parameters you select "None" for each of the axes on the Translation tab page, then 2D and 3D will be perfectly aligned (unless you have of course set rotation, scale, mirror or so).
With a None Translation, the location of the workpiece zero point is as defined in the CAD program.

Hope this makes the situation a bot more clear.

Lex.

andreas
2007-04-04
10:29 CEST

Hi,

I use Rhino 3 and Deskproto to make my 2d milling/engraving works mainly because it's simple and easy, but everything is not working as flawless as i'd like it.

I'm not sure if the problem lies within the DXF filetype itself, the Rhino DXF exporter or perhaps with the Deskproto importer. When I import the 2d file as polylines then everything is OK except for the fact that Deskproto generates a lot of drilling points along the curves whitch make the job slower and sometimes mess up the small details. Now I tried to export from Rhino as Splines and the "drilling paths" are gone, however they "took" along some segments of the curves.

I made a picture that describes the problem. Left half of the image uses polylines and you can see the many drilling points along the curve. Right half of the image has only the essential drilling movements but thre's also a missing part of the curve.. I've tried many different settings, but the drilling positions don't seem to depend on the polyline detail.

Maybe You have some suggestions on how I could get complete curves(polylines) without any "parasite" drilling movements?

Yours

Andreas Annama

Clinton
2007-04-04
12:56 CEST

Hi Lex, thank you, you where spot on.

In the 3D geometry under translation, is I select "none" for XY it aligns perfectly. I assume this now means that if I created my part on the zero access and it's 66mmX66mm, my min machining area will be X-33 Y-33. So now I understand why I see the translate co-ordinates are shown in the 3D can just be copied to 2D translate. This saves problems trying to zero you machine and line up 2 sided milling.

Picture below to explain:

Clinton
2007-04-04
13:13 CEST

Andreas, I am not sure if this helps as I don't have Rhino but in Vectorworks if you create text, then convert truetype to polylines and then further convert that to lines, then export to dxf, the contours of the fonts are converted perfectly in Deskproto. (see above)
My only problem now is to find a single line font :)

GERY
2007-04-04
18:49 CEST
Hi all, hummm my english is really limited ...

your font look curiousely segmented...
An other way with rhino, i import logo from illustrator in *.ai
and i got no problems....if you can try it..????

andreas
2007-04-05
11:26 CEST
Hi,

The problem seems to lie within Rhino's own text generator, since I haven't had problems with shapes imported from EPS or AI formats.. Strange...

Lex
2007-04-05
12:44 CEST

Dear Andreas,

It might help to play around with the DXF export settings in Rhino. A problem with DXF is that Autodesk changes the DXF file specification with each new version of Autocad, and these versions are not always 100% compatible.

I always use the oldest possible version (Release 12) for optimum compatibility (see the picture of this Rhino dialog). Note that in newer versions you can export Curves as Splines. Don't, as DeskProto does not 'see' the splines.
The same will apply to DXF export from any other CAD program: choosing R12 DXF will force the program to convert splines to polylines.

Anyway: please feel free to email me the two DXF files shown, then we can analize them and see what is wrong. Interesting is that the missing line segment also looks queer in the left picture: it is not a fluent curve.

Lex.

PS: Clinton, you are perfectly on target with your using the same Translation values in both 3D and 2D.



page 1 of 3