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Arc with straight segments with loft

Kai_himselfKai_himself Member Posts: 43 ✭✭
I made three sketches:
1x Loft, i choose the Loft tool and select all intersections. The segment are not straight, they are bend.
1x Loft with Guides, i draw two outside outlines at every segment and choose them as guidelines. This wont work... i dont know why ?!
5x Loft, i make every segment with one loft, this works the segments are straight.

Is it possible to to it with only 1x Loft and right guidelines ?
Why are my guidelines are wrong ?

Best regards


  • NeilCookeNeilCooke Moderator, Onshape Employees Posts: 4,228
    No, 5x is the way to go.
    Director, Technical Services, EMEAI
  • billy2billy2 Member, OS Professional, Mentor, Developers, User Group Leader Posts: 1,779 PRO
    No, an arc to a line has an abrupt change in curvature at the end of the arc/line. Surfaces want/must try to smooth things out. 

    It's the same reason you can't have a spline that makes a corner.

    If you want straight lines, then change your arcs to ellipses and maintain tangency across the boundary. Or, connect the lines with splines and maintain curvature across boundaries.

  • Kai_himselfKai_himself Member Posts: 43 ✭✭
    ok, Thank you very much and have a nice weekend :)
  • Evan_ReeseEvan_Reese Member Posts: 1,356 PRO
    Rhino has an option in their loft tool for straight sections like this, and I've missed it from time to time. I've considered writing my own FS for this at some point, but it's not super high on the list.
    Evan Reese / Principal and Industrial Designer with Ovyl
    Website: ovyl.io
  • steve_shubinsteve_shubin Member Posts: 748 ✭✭✭✭
    edited May 6

    In the case of what you’re modeling, you could also use a sweep


    There’s two different parts studios in the doc
    Look down in the lower left for the two tabs

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