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Loft?

andyandy Member Posts: 17 ✭✭
Hi, Apologies if I have missed something simple, but I haven't seen a loft feature. A search of the help files didn't find anything and likewise couldn't find anything in the forum about it. 

If its not there already I'm sure it must be in the works. Any timeframe for this?


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Answers

  • lougallolougallo Member, Moderator, Onshape Employees, Developers Posts: 1,849
    Loft is not currently in our toolset but we are aware of the missing feature and hope to deliver something awesome in the coming pushes..  Hang tight..
    Lou Gallo / PD/UX - Support - Community / Onshape, Inc.
  • andyandy Member Posts: 17 ✭✭
    Thanks Lou, Good to know.
  • scott_harrisscott_harris Moderator, Onshape Employees Posts: 60
    Please post (or send in) example cases that you need to work.
    Scott Harris / Onshape, Inc.
  • andyandy Member Posts: 17 ✭✭
    Hi Scott, 

    Examples range from simple to complex. Here is some packaging that lofts from a circle to a lozenge shape.





    And here is a shoe sole that used alot of trimmed surface extrudes to give complex 3D curves to loft between.




  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 1,484 PRO
    That's a nice looking sole. Thanks for sharing.
  • scott_harrisscott_harris Moderator, Onshape Employees Posts: 60
    Thanks Andy... These are great examples. 
    Scott Harris / Onshape, Inc.
  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 1,484 PRO
    yes! now that's a loft. Let's see you make that in one feature!


  • darren_henrydarren_henry Onshape Employees Posts: 85
    I thought that was a flat.
  • christoph_schmitzchristoph_schmitz Member Posts: 11
    edited April 2015
    Here's a boomerang shape that I'd love to re-create in a parametric fashion:

    http://www.thingiverse.com/thing:28662



    That one I made using box modeling and subdivision surfaces in Blender.

    Constructing an outline like this in Onshape is easy enough as is, but the cross-section of the wings is what I haven't been able to create yet. As far as I understand, in parametric CAD one could either use a loft between the top and bottom outlines, or sweep various kind of edge profiles around the perimeter.

    Regards,
    Christoph
  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,448 PRO
    Few examples for loft needs on furniture design, handles and dust extraction piping.


    image

    imageimageimageimageimageimage
    //rami
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    The easiest thing to loft is the hull of a sailboat. Except at one end:
    One of the hardest things to loft is the bow of a sailboat.
    (Lofting by conventional means is almost impossible, unless you're dealing with a cutoff bow, like an Optimist dinghy)

    Here's another challenging shape, also to do with boats (The underside, which we cannot see, is significantly shaped in a way which is difficult to model, and the side flukes are twisted in a way which is not evident here, and difficult even to measure):image
  • scott_harrisscott_harris Moderator, Onshape Employees Posts: 60
    These are great example... THANKS.
    Scott Harris / Onshape, Inc.
  • fastwayjimfastwayjim Member, OS Professional, Mentor Posts: 219 PRO
    I think propellers and fan blades are some classic examples of lofts (or I should say "swept lofts"), what would be cool is if you could have a way of capping it off nicely at the end too.

    Creo has a feature called a Variable Section Sweep, and goes something like this:

    1. Create a starting cross section.
    2. Create guide curves which pierce the initial cross section.
    3. Create the ending cross section, and any other intermediary cross sections, which also pierce through the guide curves.
    4. Create the VSS feature, by referencing the sketches.

    It's hard to explain, but it is more powerful than SW's loft with guide curves or sweep with guide curves. In addition, you can use it with the "trajpar" (trajectory parameter) command which is extremely powerful, and allows for the cross section to change driven by an equation. An example of this is when you want to create a braided wire through a 3D trajectory. In SW, you need to create swept surfaces (with z rotation), then sweep through the curves. In Creo, it is all in one single feature.

    Just like all things Creo, however, it is anything but intuitive to learn how to do. Here is an example of the geometry:


  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    One enhancement to "Sweep" which OnS might be able to implement quite early, which would be beneficial, would be "Twist along path".
    This was one of the most underutilised features of the Solidworks Sweep command, because in addition to allowing a sweep section (such as a bunch of wires) to twist along curved paths, when applied to a straight path it was a much easier way of modelling springs and screw threads than the rather laborious Helix-based method. It could be further improved (especially in the screw thread case) by including a "Pitch" option for driving the rate of twist.
  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,448 PRO
    3dcad said (in Negative fillet thread):

    Here's example of simple shape that takes less than 3 minutes to program and run with cnc (ball head router) and far longer to model in 3d. If someone want's to give it a try, ballhead R=4mm, depth on both ends = 2mm, depth on intersect = 1mm


    I suppose it's a loft (though it looks like sweep). 
    I would like to have any system to act like spinning router to create grooves and shapes. It's frustrating to create dozens of planes and revolves to replicate spinning router grooving the top of panel with different depths. And to make it even better, act like 5-ax router where router shape grooves in different angles.  
    //rami
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    edited April 2015
    Solidworks has this capability, in theory -- although the times I have tried it it has varied in success. It is limited to analytical geometry, not spline-based.
    They call it a "Solid sweep"; I presume it produces a number of solids along the sweep path, then produces a smooth solid through their silhouettes, then boolean subtracts that solid from the target.

    BTW - @3dcad: all sweeps are lofts. Sweep is a way of automating the production of a loft for the special case where all the loft sections (profiles) share the same character. The process of allocating loft planes and placing sections on them happens "behind the curtains", although some packages allow you to preview these, to help with troubleshooting if the section cannot be produced at some point along the path, or if successive sections intersect with each other because the path curves too tightly.
  • TonyNoTonyNo Member Posts: 2
    Loft would be appreciated.
  • FloFlo Member Posts: 1
    When thinking about twisting lofts, it would be very helpful to have notwisting lofts a s well. Many solid and suface modelers tend to twist stuff. E.g. going from a hexagon to a circle it can I have seen more than 360° of twist making it an hourglass shape.
  • caradoncaradon OS Professional, Mentor Posts: 300 PRO
    In SOLIDWORKS, quite frankly, I use the loft features only very rarely these days. Boundary (curve network in other CAD?) gives better results most of the time. Exceptions are surfaces that have a singularity (loft from curve to point, 3-sided surface). Sometimes loft is better in those situations.

    Dries
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭
    Boundary surfaces give equal priority to the curves along all four edges, whereas lofts treat two of the edges as pre-eminent in their influence. When the "flow" of a shape is mainly in a single direction, I find lofts tend to work better for me.
    But Solidworks certainly had problems respecting edge tangency accurately for lofts with guide curves, at least it used to. And I think that's why most users switched so enthusiastically to boundary surfaces...
  • felipe_4felipe_4 Member Posts: 3
    Hulls too,


  • nic_tauroanic_tauroa Member Posts: 8
    Lofting for long bodies with changing profiles (plane body)

    Lofting from 1 profile to another, circle to square, oval to hexagon etc.


    Director/Designer
    Eva Mechanica Ltd
    http://eva-mechanica.co.nz
  • nic_tauroanic_tauroa Member Posts: 8
    I also do a lot of automotive component design, and I need loft for the changing profile for optimum air flow.



    This example I loft cut my part to go from an oval that mounts to an cylinder head, to a circle that is the internal profile of individual throttle bodies.
    Director/Designer
    Eva Mechanica Ltd
    http://eva-mechanica.co.nz
  • 3dcad3dcad Member, OS Professional, Mentor Posts: 2,448 PRO
    @nic_tauroa  Nice plane! Is that yours?  ;)

    //rami
  • nic_tauroanic_tauroa Member Posts: 8
    @3dcad yea i drew it while I was doing my solidworks professional training. I got bored during one night after one of the lectures and drew it.

    I know much more now than I did then and could make it much better, but I still like it. 
    Director/Designer
    Eva Mechanica Ltd
    http://eva-mechanica.co.nz
  • moengineeringmoengineering Member Posts: 23
    @3dcad yea i drew it while I was doing my solidworks professional training. I got bored during one night after one of the lectures and drew it.

    I know much more now than I did then and could make it much better, but I still like it. 

    Hello @nic_tauroa

    SolidWorks? Looks like SolidEdge.


    Whatever. Lofts or Bending from circular to rectangular would be necessary for my work. hopefully this will be possible soon with OnShape.


    Best regards
    Martin
  • nic_tauroanic_tauroa Member Posts: 8
    @moEngineering The intake plenum was drawn in Solidedge, all other drawings are produced in Solidworks.

    I leased Solidedge for 3 months, but found it too resource hungry on my computer vs Solidworks, but I wanted to lease my software rather than buy a license as I am a contractor.

    I bit the bullet bought Solidworks 6 months ago, and my contracting has taken me into CNC/CAM programming and Teaching so I haven't touched it since....

    Its a shame OnShape wasnt 7 months earlier ;)
    Director/Designer
    Eva Mechanica Ltd
    http://eva-mechanica.co.nz
  • Wesley_NWesley_N Member Posts: 17 ✭✭
    edited April 2015
    3dcad said:
    3dcad said (in Negative fillet thread):

    Here's example of simple shape that takes less than 3 minutes to program and run with cnc (ball head router) and far longer to model in 3d. If someone want's to give it a try, ballhead R=4mm, depth on both ends = 2mm, depth on intersect = 1mm
    I suppose it's a loft (though it looks like sweep). 
    I would like to have any system to act like spinning router to create grooves and shapes. It's frustrating to create dozens of planes and revolves to replicate spinning router grooving the top of panel with different depths. And to make it even better, act like 5-ax router where router shape grooves in different angles.  
    I too would like an easier way to replicate a 3-axis or 5-axis cnc toolpath. I was able to create your example after a couple false starts. It was interesting to create the same toolpath in Alphacam in a couple minutes and see it match exactly to the solid model.

    https://cad.onshape.com/documents/60ffe7f9e69045cda9c2a85b/w/4cdf03871d1a437a867cdd00/e/dddfbd450a7a4ca69a261c2e

    Other paths I was struggling to recreate in Onshape were a v-groove path and a flat end tool with a 45° sloping lead-out.



    http://www.keystonecollections.com/ - Handcrafted Furniture                                   http://www.newswangerpen.com/  - Fine, handcrafted writing instruments
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