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IndustryArena Forum > CAD Software > Uncategorised CAD Discussion > Looking for easy workflow 2.5D CAD
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  1. #1
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    Looking for easy workflow 2.5D CAD

    Hi, hopefully this isn't a repeat question, but I had a bit of a search and found many questions but no good answers.

    My part-time (almost "hobbyist") workflow uses 2D CAD - often my PCB editor which outputs layered DXFs - into SheetCAM, to mill the odd 2.5D part out of materials like HDPE. It works well, but is slow to design everything in 2D and iterate.

    What would make more sense is being able to quickly and simply draw everything in 3D, using simple 2D extrudes say with fillets for ballnose cutters etc, then export a 2D DXF with predefined layers (or even go straight to G code). The idea is to speed up the design / drawing phase, especially when doing tricky things like using the edge of a ballnose cutter to chamfer something.

    But I can't find anything. Alibre does the drawing part quite nicely, but doesn't output DXF any more, but when it did (of if I pay) there was no way to export each operation on a different named layer. Various other free or affordable 3D tools are very slow and horrible to draw stuff and/or have similar DXF export limitations. DraftSight draws paths in 3D quite well, but has no solids visualisation ability that I can see.

    I can't afford a $5k CAM package, and I only want to do 2.5D at this stage.

    And there it is. Just wondering if I'm overlooking any obvious answers.

  2. #2
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    Quote Originally Posted by adx View Post
    Hi, hopefully this isn't a repeat question, but I had a bit of a search and found many questions but no good answers.

    My part-time (almost "hobbyist") workflow uses 2D CAD - often my PCB editor which outputs layered DXFs - into SheetCAM, to mill the odd 2.5D part out of materials like HDPE. It works well, but is slow to design everything in 2D and iterate.

    What would make more sense is being able to quickly and simply draw everything in 3D, using simple 2D extrudes say with fillets for ballnose cutters etc, then export a 2D DXF with predefined layers (or even go straight to G code). The idea is to speed up the design / drawing phase, especially when doing tricky things like using the edge of a ballnose cutter to chamfer something.

    But I can't find anything. Alibre does the drawing part quite nicely, but doesn't output DXF any more, but when it did (of if I pay) there was no way to export each operation on a different named layer. Various other free or affordable 3D tools are very slow and horrible to draw stuff and/or have similar DXF export limitations. DraftSight draws paths in 3D quite well, but has no solids visualisation ability that I can see.

    I can't afford a $5k CAM package, and I only want to do 2.5D at this stage.

    And there it is. Just wondering if I'm overlooking any obvious answers.
    I don't know how complicated you get but Google Sketchup Pro does 3d and outputs many formats. Maybe Vectrics Vcarve Pro would work also. Nice thing about Vcarve it will generate your Gcode and you can bypass the Sheetcam step altogether. Not bad for $600.00 USD

    Mike

  3. #3
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    ViaCAD and CamBam will do all you want - 2d or 3d.


    Martin.

  4. #4
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    Thanks for the replies.

    I guess what I do is fairly complex for 2.5D - see the optical alignment fixture pic attached - parts milled from HDPE with a 6mm square ended tool from one side. I've made about 10 of these (some with differences), so 2.5D and in-house production using a retrofitted mill with no toolchanger worked quite well. Where it falls over is for a one-off - not difficult, just the hours of design once it's all simulated and ready to go.

    I kind of like Sketchup's ease of use, but it seems to be aimed more at visual / (renderer) designers than MCAD. Viacad entered my sights at the same time I found Draftsight, but apparently I got all excited I had found my "2D solution" (again...) and didn't look further at ViaCAD, which I will now.

    Although I like SheetCAM (a lot - compared to doing it manually or a rudimentary G-code converter), I could move to Cambam if it could simplify my workflow. Vcarve is a bit more "graphics" industry but I like the features, like fluting, which is heading towards 3D but still relying on the tool to form shapes.

    I'll spare you the whole story of how I'm still searching for the ideal (for me) 3D and 2D CADs after being introduced to Solidworks & SurfCAM around 1998 (at work), but there does seem to be a big gap in capabilities still. What I'm trying to do now is an example - any 2D CAD worth its salt can work with layers and export to DXF without any problems, but I am yet to find any 3D tool that can do the same thing (or lots of other standard 2D stuff), yet all 3D tools have excellent 2D sketching which I've long looked for in workhorse 2D...

    I had a tinker with FreeCAD lastnight and it still has some way to go, but I did manage to get a workable DXF out of it. I guess I could write a converter to pick out features in ranges of z heights and put them onto named layers, that file would then automatically update a Sheetcam job.

    I'll have a look at ViaCAD when I can, and I'll post here if I do find something works.
    Attached Thumbnails Attached Thumbnails IMG_9980 crop CFX.jpg  

  5. #5
    Community Moderator ger21's Avatar
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    I really don't think that anything exists to do what you're looking for.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
    http://www.g-forcecnc.com/jointcam.html

    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  6. #6
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    I've made a very quick video (in realtime) that shows how you can draw something similar (simplified) to your pic in ViaCAD and create the toolpath in CamBam in both 2d and 3d with a dxf and stl file respectively.

    2012-05-19_1857 - Hammering's library


    Martin.

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    Thanks, it's good to see the tools in actual use, especially Viacad since there's little in the way of screenshots on their site. I really like the way it draws, if I get time I'll bite the bullet and sign up for the trial.

    SheetCAM imports and selects 2D drawing data very similar to CamBam (actually it's a bit different but the functionality looks roughly the same), but once each operation is set up for a named layer, there's no need to re-select countours to attach to each operation when updating the drawing from a DXF (wouldn't surprise me if CamBam does this too).

    Because the design and optimisation is often an iterative process, it's slow and risky to have to re-pick all the features out every time a change is made, which pretty much limits design to 2D, because I haven't yet seen a solid modeller which can output sketch-extrude features to named DXF layers (3D wireframe CADs like DraftSight do it natively).

    For example in that piece facing you, there's layers for holes that are machined from the surface, the main pocket, holes that are machined from its start height, a step for the sensor to sit in, and finally a perimeter / centre cut out with tabs - and it's important to get the machnining in the right order and direction because HDPE burrs badly, cutter ramping etc.

    My clever idea was to write something which parses a 3D DXF and separates features within a range of z-heights to different named layers (they can stay 3D because SheetCAM ignores Z), for semi-automagic updates into the CAM. Not all solid modellers output 3D DXFs though.

  8. #8
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    Unless there are some features on your pictured part that I can not see, then it looks like a straightforward 2d machining job and is the sort of thing that could be done comfortably with ViaCAD/CamBam.

    It's just a matter of creating a few machining operations (MOPs)and combining them together in the right order.

    ViaCAD does output 3d DXF files (solids and/or curves), but I certainly wouldn't be looking at trying to machine that part by using these options.

    Layers are available in ViaCAD and can contain any mix of geometry, layers are also there in CamBam too and curves from any combination of layers can be used to create a MOP.

    Geometry can be edited within CamBam, either with its own tools or by cutting and pasting from a second instance of CamBam, which you can use for all your rough editing without fear of damaging your 'master' file.





    Martin.

  9. #9
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    Attached pic from left to right is simulation in CncSimulator, Cutviewer trial (think I'll buy that), and the "blue" layer of my PCB design package.

    So yes it probably wasn't the best example - easy enough to design in 2D in fact I drew everything on the same layer (I used different layers to get the stack of 3 parts in registration).

    Designing in 3D seems like a nice idea, but the problem is then that for complex parts there's then a ton of overlapping contours all on the same layer, and any change they have to be sorted out again.

    I really need to try both ViaCAD and CamBam to get a feel for what you're saying, though I think I grasp it. If ViaCAD can output a layered DXF of any sort (2D or 3D doesn't matter) from a top view of a solid part, then problem solved for my SheetCam workflow. Sounds promising.

    I was originally interested in CamBam as a way to draw parts on the fly (next to the machine) but it doesn't seem to have the raw power of a full-on CAD, another option though.

    Thanks for all these pointers, I'll have to do some checking and will make sure to post back when I have an answer.
    Attached Thumbnails Attached Thumbnails cfx_bu-example.png  

  10. #10
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    I've just been trying ViaCAD and yep it does pretty much exactly what I want (outputs DXFs which update a SheetCAM job with layer names intact), it's a pretty good 3D MCAD too, and a good 2D CAD in the same workspace.

    Thanks for that pointer. Not 100% certain yet as I've been here before, but it looks like the way to go.

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