28 Replies Latest reply on Oct 15, 2015 7:51 PM by Dennis Bacon

    How to export dxf w/ closed loop vectors?

    Douglas Madaras

      Novice here- My CNC guy requires dxf files. Those I exported have "broken vectors". He needs them 'connected'. It seems all the lines are being converted to a series of short line segments- individual vectors.

       

      Oy- the learning curve is grand. Any assist is appreciated.

        • Re: How to export dxf w/ closed loop vectors?
          Bob Van Dick

          Douglas,

           

          I downloaded your dxf file and didn't find what you are describing.  They were just lines and arcs, 12 entities in all.  Maybe there is something going on at his end.

          This is what my export options look like.

           

          Bob

          • Re: How to export dxf w/ closed loop vectors?
            Bob Van Dick

            Douglas,

             

            I have brought this file into our laser programming software and works fine, no short lines...

             

            Bob

            • Re: How to export dxf w/ closed loop vectors?
              Douglas Madaras

              I appreciate the help so far but my skull must be too thick or I am missing something real obvious. Maybe a better question is:

              How do I join lines so my save as dxf come out as two separate entities and not 12?

                • Re: How to export dxf w/ closed loop vectors?
                  Bob Van Dick

                  Douglas,

                   

                  I don't believe what you are asking can be done in SolidWorks, and to tell you the truth, I can't understand why that would need to be done.  Any programming software I have ever used would have no problem attaching a toolpath to the dxf file that SolidWorks is exporting.  What exactly needs to be accomplished with this dxf file?

                   

                  Bob

                    • Re: How to export dxf w/ closed loop vectors?
                      Douglas Madaras

                      Bob- thanks.

                      My task is to create designs for assorted plywood cut outs. Some abstract, others very basic as attached. The more ornate- the more unjoined lines there are- the more time it takes the cnc guys to prep my drawings to do their work. I have sent them dxf files from other programs in which I can join polylines without any grief. From SW it seems impossible at least from my end. My whole purpose in getting into SoldWorks was to be able to articulate 3d concepts and to provide dxf files for cnc. My cnc guy has ran the issue by others in the field and they all say that the files I send have unjoined lines where from other programs- same sample file, all are joined.

                       

                      It seems to me, being a noob and all to SW that there would be a basic 'join polyline' or 'entity' command by which a simple rectangular shape can be joined into one entity....

                       

                      ...I should add, after contacting SW desk help it was suggested that I run my SW designs through DraftSIght as a means to join the lines as desired. This seems counter productive. That said, I am on an uphill learning curve so it all seems a bit challenging at the moment.

                       

                      Your assists have been helping to ease the pain....thx.

                        • Re: How to export dxf w/ closed loop vectors?
                          Bob Van Dick

                          Douglas,

                           

                          Sounds like a limitation of the cam software they are using.  Any program that would require that two lines that come together with no space in between would require being fused together would be worthless in my line of work.  What software are they using?  Is it some bargain basement cam system?  What kind of machine are they using?  Is the software built into the controller of the machine cutting out the parts?  If not, I would change to a different CAM system....

                           

                          Bob

                          • Re: How to export dxf w/ closed loop vectors?
                            Bob Van Dick

                            Douglas,

                             

                            Draftsight may be a possibility, I don't know much about it.  I only use it for exporting newer version dxf files to older ones that Cadkey can read.  Draftsight looks like an AutoCAD clone....I hate AutoCAD.  It has got to be one of the most unintuitive software packages that I have come across.  I will keep trying to see if I can figure something out that may help you....

                             

                            Bob

                            • Re: How to export dxf w/ closed loop vectors?
                              Chris Dordoni

                              Hi Douglas,

                               

                              Part of the issue here is that SolidWorks uses splines or segmented polylines for all curves exported to dxf.

                               

                              If you have a 2d sketch with an arc, or 3d sketch parallel to the view direction, that has an arc, you will get an arc in the DXF. So in general, if you have not drawn it as an arc in in a sketch SolidWorks, you are not going to get an arc out from SolidWorks.

                               

                              Most 2d CNC cutting machines do not use splines. They will be converted to segmented polylines that may contain thousands of short line segments.

                               

                              I have not used Draftsight, so I do not know if it can generate arcs from splines. If it does not, I would highly recommend you invest in an application that will convert splines to arcs, or fit arcs to segmented polylines. This will result in fewer headaches.

                               

                              Its possible the cutting service may have software that can do this. One reason to do it yourself is that conversion to arcs may introduce an undesireable change in the shape of the curve. The tolerance setting for the conversion to arcs may not address this, so sometimes its necessary to break the spline up into smaller sections.

                        • Re: How to export dxf w/ closed loop vectors?
                          Kevin Chandler


                          Hello,

                           

                          I'm not replicating your issue and generally agree with the previous replies.

                           

                          However, you can use DraftSight to convert your separate sticks and rings into the two entities you asked for above by using PEDIT (AutoCAD's term but an alias for DS' POLYEDIT).

                           

                          Run this command and select one of the entities. Since none of the original are polylines, you're prompted to convert the selection to a PLINE. Type "Y" and Enter.

                          Of the PEDIT options, you want "Join", so type "J" and press Enter. Select the entities to join into one PLINE and press Enter.

                          You're still in PEDIT command, so type "X" to exit this command--BUT BEFORE YOU DO, review the other options and you'll see "Open".

                          It's opposite command is "Close", but since "Open" is only shown, that means all of your entities were joined at their intersections--no gaps.

                           

                          My babble above is in the attached DXF, FWIW.

                           

                          Cheers,

                           

                          Kevin

                            • Re: How to export dxf w/ closed loop vectors?
                              Bob Van Dick

                              Kevin,

                               

                              That's good to know.  Sometimes there are occasions when we get dxf files which have been vectorized and contains thousands of little lines that may be only .001 long.  They drive our laser crazy.  I think this may do the trick in reducing the amount of entities in a vectorized dxf file.  Now I have two things to use Draftsight for....

                               

                              Thanks,

                               

                              Bob

                            • Re: How to export dxf w/ closed loop vectors?
                              David Aberizk

                              The best way I've found to solve your issue is to import the DXF into Corel Draw and use the 'Join Curves' command.

                               

                              From there, you can re-export.

                               

                              I do this all the time for Silkscreeners that require closed loops with a fill.

                               

                              I wish SolidWorks did this automatically.

                              • Re: How to export dxf w/ closed loop vectors?
                                Melissa Newby

                                Can you make a block from your sketch and then save as a dxf? I know this won't make it a polyline, but it does make it one/two entities.

                                 

                                I don't have to send files to CNC  people, so I may be completely off here.

                                • Re: How to export dxf w/ closed loop vectors?
                                  Dennis Bacon

                                  Your image is probably constructed from splines and there might not be arcs that are applicable to define the exact shape. All the cam software I  have used requires arcs and lines in order generated the code. That is how the machine reads it. One continuous polyline is not going to cut it (from my experience). Years ago (many) I downloaded a "Lisp" file to run in Acad that did a pretty fair job on converting a bunch of short lines into arcs. Then (I think it was in the 90's) an upgrade in my cam software did it for me. It would be interesting if you could upload that shape (one of the 50) so we can take a look at it see what we can do with it.