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  1. #21
    Forum Deity SEANT's Avatar
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    Now we're into my own specific problem. I've never had/used Illustrator. I'm not involved with CNC processing as much any more, else I probably would have invested in the package.

    I do have an old version of CorelDraw, however. And I did have direct access to a Pen/Knife plotter with CorelDraw support, which was better at reproducing curves compared to what it would accept from a DXF file.

    Perhaps there is some intermediate step, CAD/Vector file - PostScript - NC/G-Code, that the DXF files miss out on, thus forfeiting all of the Spline geometry.

    Or, based on this quote:

    Quote Originally Posted by spiderartist View Post
    My machine works fine with curves created in vector illustration software, such as CorelDraw or Adobe Illustrator. Sometimes when I import a dxf file into either program, it works fine and sometimes it doesn't. . . . .
    Nurbs Curves that only have features of Beziers - Splines with Degree + 1 Control Vertices (none of the higher Non-Uniform and/or Rational bits) can be processed correctly.
    Last edited by SEANT; 15th Mar 2016 at 09:16 am.

  2. #22
    Forum Deity SEANT's Avatar
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    Lee, does your school have a CNC machine?

  3. #23
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    I took 4 S shapes in AutoCAD>imported to Illustrator>exported as SSSS.dxf. The SSSS.dwg is what I created in AutoCAD as a comparison, I also made an .eps. The S.dxf was created in Illustrator and exported.
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  4. #24
    Senior Member lrm's Avatar
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    SLW210, thank you for the file. The file contains a "new" spline but not an "old" spline. I've included an S in the attached file SSSSS.dwg (5 S's). I created it by converting a polyline to a spline. I estimated the location of the CVs needed then adjusted their location after giving the PEDIT S command. I used 9 CVs to get a close approximation to your original S.

    Please convert this file to Illustrator then export as a dxf file.

    Thank you,

    Lee
    SSSSS.dwg

  5. #25
    Forum Deity SEANT's Avatar
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    The SSSS.dxf and the S.dxf are interesting, and what I think are the crux of the problem.

    The "S" in the straight Illustrator to DXF export results in combined Beziers. It actually shows as a Non-Uniform type of Nurbs, but an explode reduces it to the individual Bezier sections.


    A typical AutoCAD Spline to Illustrator import to DXF export results in segmented poly (as demonstrated by the first "S" in SSSS.dwg/SSSS.dxf).


    What would happen if the attached file is brought into Illustator? Does the Modified "S" (Red) still get reduced to a faceted Poly?

    Edit: Looking at this now on my phone I see that the attachment didn't get included. I'll have to do that when I get back to the desk.
    Last edited by SEANT; 15th Mar 2016 at 03:41 pm.

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    Senior Member lrm's Avatar
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    Quote Originally Posted by SEANT View Post
    The SSSS.dxf and the S.dxf are interesting, and what I think are the crux of the problem.

    The "S" in the straight Illustrator to DXF export results in combined Beziers. It actually shows as a Non-Uniform type of Nurbs, but an explode reduces it to the individual Bezier sections.
    I agree. The original spline with many CVs (almost 50) is broken up with EXPLODE into a series of splines with 4 CVs each which could be cubic Bezier splines. Explode cannot be used on the resulting spline but PEDIT will convert it into a polyline with hundreds of vertices.

    Here's what the translation of the AutoCAD file to Illustrator to DXF does with the four S's of the original file:
    • A "new" Spline (NURBS) becomes a polyline
    • Two arcs become 2 "new" splines
    • A 2d polyline is still a 2d polyline

    It is interesting to note that arcs are converted to splines in this process and splines become polylines. The conversion from AutoCAD to Illustrator to DXF and back to AutoCAD has made the arc a more complex object. I would expect arcs to keep their identity or at the least simplified to a segmented polyline. I would think the conversion from arc to NURBS would make it more difficult for some post processors to handle.

    What is the DXF format of a spline that has been created directly in Illustrator?

  7. #27
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    I took your DWG and ran the 4 "S's" through the posting process for our machine. Interestingly, even the 1st S (I assigned them numbers from left to right) posted properly, even being splines. I haven't run them through the controller yet but the code seems correct. I'll post the actual G code for the 4 attempts. The last one, the outline polyline, I erased the right side of the form to give it a no-kerf cut to match the others.

    1st S (from left to right):
    G90
    G0X12.8518Y-2.0555
    (Set 1 torches at 0.0000 inches)
    M00 (Program Stop)
    M58
    M70
    G3X11.6853Y-1.2292I-15.2951J-20.3539
    G3X10.4454Y-0.5476I-4.5769J-6.8570
    G3X7.8858Y-0.0023I-2.6944J-6.3682
    G3X5.2478Y-0.4091I-0.1871J-7.5431
    G3X0.6096Y-4.6842I2.7091J-7.5928
    G3X0.0014Y-7.6744I6.3663J-2.8520
    G3X1.1029Y-11.5008I8.2011J0.2891
    G3X2.3009Y-13.1100I7.0861J4.0250
    G3X3.8282Y-14.3026I4.7913J4.5616
    G3X5.5260Y-14.9738I3.6329J6.7062
    G3X6.8834Y-15.2845I4.7934J17.8211
    G2X8.9393Y-15.7040I-8.3032J-45.9475
    G2X10.8742Y-16.3968I-1.8694J-8.2683
    G2X12.3813Y-17.4890I-3.1332J-5.9093
    G2X14.9067Y-22.6163I-5.9944J-6.1381
    G2X13.1847Y-28.5227I-7.9488J-0.8867
    G2X10.3310Y-30.7523I-6.4593J5.3261
    G2X6.7983Y-31.6083I-3.7260J7.6602
    G2X2.7225Y-30.5161I-0.1795J7.4820
    G2X1.4181Y-29.4905I4.7046J7.3254
    G2X0.2355Y-28.2918I18.7906J19.7209
    M71

    2nd:
    G90
    G0X12.8504Y-2.0348
    (Set 1 torches at 0.0000 inches)
    M00 (Program Stop)
    M58
    M70
    G3X7.2225Y-15.2951I-5.1968J-5.6188
    G2X0.2341Y-28.2710I-0.4255J-8.1407
    M71

    3rd:
    G90
    G0X13.1175Y-2.1946
    (Set 1 torches at 0.0000 inches)
    M00 (Program Stop)
    M58
    M70
    G3X6.7488Y-15.3867I-5.3932J-5.5297
    G2X0.5012Y-28.4308I0.5408J-8.2773
    M71


    4th (left half of the outline form)
    G90
    G0X0.3010Y-25.4389
    (Set 1 torches at 0.0000 inches)
    M00 (Program Stop)
    M58
    M70
    G1X0.7075Y-25.6712
    G1X1.1774Y-25.9775
    G1X1.7371Y-26.2995
    G1X2.2176Y-26.5424
    G1X2.7350Y-26.7906
    G1X3.3053Y-27.0282
    G1X3.9336Y-27.2552
    G1X4.4352Y-27.4136
    G1X4.9896Y-27.5667
    G1X5.5862Y-27.6829
    G1X6.2145Y-27.7674
    G1X6.8851Y-27.8149
    G1X7.4342Y-27.8254
    G1X8.0995Y-27.7990
    G1X8.7384Y-27.7304
    G1X9.3508Y-27.6142
    G1X9.9369Y-27.4506
    G1X9.9950Y-27.4347
    G1X10.6127Y-27.2077
    G1X11.1830Y-26.9279
    G1X11.7057Y-26.5952
    G1X12.0067Y-26.3576
    G1X12.4607Y-25.9299
    G1X12.8514Y-25.4389
    G1X13.1841Y-24.9003
    G1X13.3319Y-24.5994
    G1X13.5431Y-24.0397
    G1X13.6857Y-23.4378
    G1X13.7702Y-22.7936
    G1X13.7913Y-22.2392
    G1X13.7490Y-21.5634
    G1X13.6329Y-20.9351
    G1X13.4375Y-20.3596
    G1X13.1946Y-19.8844
    G1X12.8462Y-19.3669
    G1X12.4449Y-18.8865
    G1X11.9908Y-18.4377
    G1X11.6423Y-18.1473
    G1X11.1460Y-17.7935
    G1X10.6180Y-17.4556
    G1X10.0583Y-17.1282
    G1X9.4723Y-16.8220
    G1X9.4247Y-16.7956
    G1X8.8545Y-16.5210
    G1X8.2843Y-16.2465
    G1X7.7088Y-15.9666
    G1X7.1280Y-15.6868
    G1X6.9062Y-15.5812
    G1X6.3254Y-15.3119
    G1X5.7552Y-15.0268
    G1X5.1902Y-14.7311
    G1X4.6305Y-14.4302
    G1X4.3665Y-14.2770
    G1X3.8121Y-13.9391
    G1X3.2894Y-13.5748
    G1X2.7931Y-13.1788
    G1X2.3285Y-12.7617
    G1X2.1701Y-12.6086
    G1X1.7371Y-12.1545
    G1X1.3464Y-11.6635
    G1X0.9926Y-11.1407
    G1X0.6864Y-10.5758
    G1X0.5966Y-10.3857
    G1X0.3802Y-9.8471
    G1X0.2112Y-9.2716
    G1X0.0898Y-8.6539
    G1X0.0211Y-7.9939
    G1X0.0000Y-7.3444
    G1X0.0264Y-6.6739
    G1X0.1003Y-6.0297
    G1X0.2218Y-5.4120
    G1X0.3907Y-4.8259
    G1X0.6125Y-4.2609
    M71
    G0X0.6178Y-4.2557
    M70
    G1X0.9082Y-3.6854
    G1X1.2461Y-3.1574
    G1X1.6368Y-2.6611
    G1X2.0697Y-2.2017
    G1X2.3549Y-1.9430
    G1X2.8353Y-1.5787
    G1X3.3581Y-1.2461
    G1X3.9125Y-0.9504
    G1X4.5091Y-0.6970
    G1X5.0529Y-0.5016
    G1X5.6337Y-0.3379
    G1X6.2304Y-0.2006
    G1X6.8534Y-0.1056
    G1X7.4923Y-0.0370
    G1X8.1576Y-0.0053
    G1X8.4849Y0.0000
    G1X9.1132Y-0.0211
    G1X9.7468Y-0.0792
    G1X10.3804Y-0.1848
    G1X11.0193Y-0.3168
    G1X11.6371Y-0.4699
    G1X12.2126Y-0.6389
    G1X12.8356Y-0.8765
    G1X13.4164Y-1.1246
    G1X13.7438Y-1.2830
    G1X14.3826Y-1.6632
    G1X14.6361Y-1.8533
    M71

  8. #28
    Forum Deity SEANT's Avatar
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    Quote Originally Posted by Quik&Easy View Post
    I took your DWG and ran the 4 "S's" through the posting process for our machine. Interestingly, even the 1st S (I assigned them numbers from left to right) posted properly, even being splines. I haven't run them through the controller yet but the code seems correct. I'll post the actual G code for the 4 attempts. The last one, the outline polyline, I erased the right side of the form to give it a no-kerf cut to match the others.

    1st S (from left to right):
    G90
    G0X12.8518Y-2.0555
    (Set 1 torches at 0.0000 inches)
    M00 (Program Stop)
    M58
    M70
    G3X11.6853Y-1.2292I-15.2951J-20.3539
    G3X10.4454Y-0.5476I-4.5769J-6.8570
    G3X7.8858Y-0.0023I-2.6944J-6.3682
    G3X5.2478Y-0.4091I-0.1871J-7.5431
    G3X0.6096Y-4.6842I2.7091J-7.5928
    G3X0.0014Y-7.6744I6.3663J-2.8520
    G3X1.1029Y-11.5008I8.2011J0.2891
    G3X2.3009Y-13.1100I7.0861J4.0250
    G3X3.8282Y-14.3026I4.7913J4.5616
    G3X5.5260Y-14.9738I3.6329J6.7062
    G3X6.8834Y-15.2845I4.7934J17.8211
    G2X8.9393Y-15.7040I-8.3032J-45.9475
    G2X10.8742Y-16.3968I-1.8694J-8.2683
    G2X12.3813Y-17.4890I-3.1332J-5.9093
    G2X14.9067Y-22.6163I-5.9944J-6.1381
    G2X13.1847Y-28.5227I-7.9488J-0.8867
    G2X10.3310Y-30.7523I-6.4593J5.3261
    G2X6.7983Y-31.6083I-3.7260J7.6602
    G2X2.7225Y-30.5161I-0.1795J7.4820
    G2X1.4181Y-29.4905I4.7046J7.3254
    G2X0.2355Y-28.2918I18.7906J19.7209
    M71
    . . . .
    So, based on post processing the DWG file, your Pipeline created Multiple arc from the input spline. Not a bad compromise. It sounds like a CAD jockey could send native AutoCAD splines, and your pipeline would create a reasonable facsimile.

    I suppose, though, the customer may feel more comfortable generating their own Arc recreation - to be sure they new what they were dealing with.

  9. #29
    Forum Deity SEANT's Avatar
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    Quote Originally Posted by lrm View Post
    . . . .

    What is the DXF format of a spline that has been created directly in Illustrator?
    The resultant DXF file shows the same as if there were several Degree 3 Beziers (Splines with 4 CPs) joined together via AutoCAD's JOIN command.

    Arcs changing to splines in the AutoCAD - Illustrator - DXF conversion is not a surprise. CorelDraw and, from what I hear, Illustrator do not have a pure Circle entity. They just combine 4 arc-like Beziers together. Those software packages do not support Rational splines either, so the circular elements are not 100% accurate.

  10. #30
    Forum Deity SEANT's Avatar
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    I'd be interested to know how Illustrator and/or a Post Processor would deal with the red "S" in the attached DXF (The file I was supposed to include with my post earlier this morning).
    Attached Files

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