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OpenBuilds CAM - unable to open a .dxf file

Discussion in 'CAM' started by Award, Mar 19, 2019.

  1. Award

    Award Well-Known
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    Hello,

    I've been trying to open the Geometric Trivet.dxf file (kindly provided by Ariel Yahni in the Projects section) with OpenBuilds CAM. However when I open the file I get a message saying that "Geometric Trivet.dxf contained some unsupported entities. These were ignored." and then the 3D viewer in OB CAM is blank.

    I am on day 2 of learning Fusion 360 (feels like a lot longer than two days!) so my CAD experience is pretty much zero and I can't identify what an unsupported entity is. Any pointers as to what I am doing wrong would be very gratefully received.

    Cheers

    Adam
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Here's a slightly fixed version of the DXF. I think he used Vectric for the original project.

    - I pulled the original into Sketchup with the FreeDXF plugin
    - Added a FACE
    - Merged the face with the lines
    - Reexported as DXF using the Guitarlist plugin

    trivit.PNG
     

    Attached Files:

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  3. Award

    Award Well-Known
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    Thanks very much Peter - that opens up in OB CAM perfectly. Time to make some more mess in my garage/high tech production facility.

    I've got a stupid newb question but I am assuming from this that not all .dxf files are interoperable between CAD software? The only reason I ask is that if I open up your new version of Trivit2.dxf in Fusion 360 (I wanted to see what the changes were) then it doesn't display anything.

    Alternatively I might not be doing something correctly due to my enormous CAD experience of 2 whole days ;-)

    Thanks again
     
  4. Alex Chambers

    Alex Chambers Master
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    #4 Alex Chambers, Mar 19, 2019
    Last edited: Mar 19, 2019
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  5. Award

    Award Well-Known
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    Thanks for looking Alex.

    Is this a normal problem/issue with .dxf files? In my ignorance I assumed that they are a standard format but obviously not. Should I be using another file type?

    Cheers

    Adam
     
  6. Alex Chambers

    Alex Chambers Master
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    Fusion is not happy with 3D dxf's - there are allegedly ways of getting them into Fusion, but I haven't found any that work yet.
    Alex.
     
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  7. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Those are both 2D DXFs.

    DXF has several sub formats (all proprietary Autodesk, figured out by reverse engineering mostly), IE R14, R13, R2000 etc (basically each version of autocad, had a slightly extended or different dialect)
    Open Source apps like R14 the best (;

    Inside a DXF is several kinds of entities. Lines, Polylines, LWPolylines, Points, Arcs, Circles, Splines and many more. We support Polyline the best, with some others like line, lwpolyline, arc and circle as well (but wont be as reliable as Polylines). Splines is not supported at all.

    So adding a step in between is sometimes needed to cleanup up DXFs (convert splines and arcs to polylines, flatten geometry to the same Z plane, group seperate lines into polylines (ie 4 lines in a rectangle: CAM cant understand it as is. But if the 4 lines is joined into a Polyline (one entity = the rectangle) then no problems
     
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  8. Alex Chambers

    Alex Chambers Master
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    Fusion says they contain 3d elements - I couldn't "insert" the file into a sketch and the other trick of "uploading" it (which should work for a 2d dxf as well) wouldn't work either.
    Alex. :(
    PS as the screenshot shows "layers" I also tried applying a separate sketch to each layer when inserting into Fusion - it didn't work either.
     
    #8 Alex Chambers, Mar 19, 2019
    Last edited: Mar 19, 2019
  9. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Theres nothing 3D in there... just autodesk being confused.

    Open it in QCAD or something else (;
     
  10. Alex Chambers

    Alex Chambers Master
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    Thanks @Peter Van Der Walt, I'll let @Award play with that - I was just trying to help him get it into Fusion. Yes - a file format allegedly designed to facilitate drawing exchange (hence the dxf) is one of the more problematic ones.
    Alex. :mad::mad:
     
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  11. sharmstr

    sharmstr OpenBuilds Team
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    I put it into fusion this morning. I'll post it up later.
     
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  12. Alex Chambers

    Alex Chambers Master
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    Thanks @sharmstr - please tell us how
    Alex.
     
  13. Alex Chambers

    Alex Chambers Master
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    Hi @Award, I just took the first dxf (from projects) started a new sketch and INSERTED it (insert dxf)) into Fusion with no problems.
    Alex.:D:D:D


    Trivet.png
     
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  14. Award

    Award Well-Known
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    Thank you all very much for the help - I have another steep learning curve ahead of me!
     
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  15. Alex Chambers

    Alex Chambers Master
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    I suspect the changes Peter made in Sketchup are upsetting Fusion - I don't know whether @sharmstr was working with the original file or Peter's modified version. If she knows a way to get that one into Fusion I'll be interested as it might work with some dxf's I'm failing to load.
    Alex.
     
  16. sharmstr

    sharmstr OpenBuilds Team
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    That's how I did it. :)
     
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  17. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    (; Let me let you in on a secret.

    Finding files online is the quickest path to frustration, learn to draw early on. Sketchup is Easy! Fusion360 is technically better. Its a skill that makes using your machine more possible than you imagine. Being in control is the best. And troubleshooting random files from online is something you'll then never do again.

    I have been using Sketchup for almost all my projects (2.5d work) with OpenBuilds CAM. Sketchup -> Guitarlist DXF export -> CAM. Could not be easier


     
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  18. Alex Chambers

    Alex Chambers Master
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    Very true @Peter Van Der Walt - or of course draw in Fusion, cam in Fusion, post in Fusion, cut.
    Alex.:rolleyes::rolleyes::rolleyes:
     
  19. Award

    Award Well-Known
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    I think you both misread my first and second post.

    I could open file 1 from Open Builds Projects in Fusion and view it (you can just upload it)

    What I couldn't do is view file 1 in Open Builds CAM.

    Peter then modified that file 1 in SketchUp, etc and I could then successfully open it in Open Builds CAM but when I subsequently tried to look at his modified file 2 in Fusion to see the difference between file 1 and file 2 it displayed as a blank.

    What I was trying to gently highlight is that Open Builds CAM can't handle all .dfx files (specifically in this case Vetric .dfx files) as they have different implementations which Peter alluded to in his subsequent post. In all fairness it also looks like Fusion doesn't like SketchUp files that have been modified by Guitarlist dfx export plugin so it all becomes a bit of a circular problem.

    I think the takeaway point for a newbie is that the work flow chain is key as it is clear that interoperability is a problem. So in the context of this discussion (obviously other myriad permutations apply):

    Sketchup -> Guitarlist DXF export -> Open Builds CAM
    Fusion 360 -> Fusion CAM

    Cheers

    Adam
     
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  20. Alex Chambers

    Alex Chambers Master
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    Hi Adam, no I didn't misunderstood you - I realised you were trying to get trivet2 into Fusion. I only went back to the first version to see if there was any underlying problem with it. Dxf's can be a pain when used to transfer files between different platforms - often causing difficulties as Peter has pointed out. Let us know how you get on with the trivet.
    Alex.
     
  21. Award

    Award Well-Known
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    This is a bit of a side note but I thought I would try and view the two files in Notepad just to understand what the difference is. They aren't even vaguely the same so I had a look at the DXF Reference:

    https://images.autodesk.com/adsk/files/autocad_2012_pdf_dxf-reference_enu.pdf

    The first file from Vectric has a resemblance to the above specification but the second file from SketchUp and the dxf plugin doesn't. However the second file displays in OB CAM so having a quick look at the dxf-parser.js on GitHub:

    OpenBuilds/cam

    It looks like the code does parse splines so I'm assuming that the the three-dxf viewer is what doesn't support splines?

    Cheers

    Adam
     
  22. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Pull requests welcomed. Upstream, Circle/ Arc Issue (Exported DXF from Autodesk Inventor) · Issue #8 · gdsestimating/three-dxf got support for splines but I dont think we ever completed the work under the LW days, which subsequently became CAM when I joined OB.
     
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  23. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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  24. Award

    Award Well-Known
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    LoL. I was just looking at dxf-render.js to see where the error message came from and wondered if you had anything to do with laser web!

    Having had a look at three-dxf they've "only" (I'm not criticising because the full dfx spec is a beast!) implemented a subset of the entities.

    Thanks for the input now I better get back to learning Fusion.

    Cheers

    Adam
     
  25. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    True, (; only the ones appropriate to CAM - I tried all them in the LW days and this one handled "most" files thrown its way. The few complaints here and there are always solved with a "convert to polylines" reply (;
     
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  26. Award

    Award Well-Known
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    Ha! Ha! If I knew how to use any CAD software then the "convert to polylines" would have worked.
     
  27. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    (; and thats exactly back to:
    :D now go learn Fusion! Lol!
     
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  28. Award

    Award Well-Known
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    Here's a picture of the dreaded Trivit which I have converted into a lid from scrap plywood using OB CAM and a scrap plywood box that I made with JointCAM.

    Thanks again for all the help

    Adam

    Box.JPG
     

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