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Why is this sketch not fully defined?

lizardonabikelizardonabike Member Posts: 6
edited February 5 in Community Support

What am I missing here to fully define this sketch? This often happens to me when working with the arc tools.

Screenshot 2026-02-04 at 11.44.30 AM.png

Best Answers

  • Matt_ShieldsMatt_Shields Member, Onshape Employees Posts: 916 PRO
    Answer ✓
  • CADNurdCADNurd Member Posts: 64 ✭✭
    Answer ✓

    Arcs are segments of a circle and circles need to be given a size. Also, if you're planning on extruding something with ready-made fillets, that's generally not the way to go. Fillets are better added to the solid model at the very end.

    Unemployed Onshaper - operating on European time. More of me here ➤ https://linktr.ee/Liam.G

Answers

  • Matt_ShieldsMatt_Shields Member, Onshape Employees Posts: 916 PRO
    Answer ✓
  • CADNurdCADNurd Member Posts: 64 ✭✭
    Answer ✓

    Arcs are segments of a circle and circles need to be given a size. Also, if you're planning on extruding something with ready-made fillets, that's generally not the way to go. Fillets are better added to the solid model at the very end.

    Unemployed Onshaper - operating on European time. More of me here ➤ https://linktr.ee/Liam.G

  • nick_papageorge_dayjobnick_papageorge_dayjob Member, csevp Posts: 1,058 PRO

    Put the dim to the flats of the box, not to the tangent points of the radii. That is the design intent 99.9% of the time. Then, put a separate dim for the radius. Set both radii equal to each other.

    I also agree with the comment to add the radii as a separate feature in 3D, instead of inside the 2D sketch, as a general cad principle,

  • jim_zamecnikjim_zamecnik Member Posts: 12

    Constraints, and coincidence between sketches has been the biggest challenge for me. I spend literally hours sometimes trying to figure out why a sketch won't turn black or a loft won't render. I haven't found a good tutorial or YouTube on troubleshooting these situations. I've only been working with Onshape (and 3D CAD at all) for a week; I knew it wouldn't be easy but hopefully a breakthrough is coming!

  • nick_papageorge_dayjobnick_papageorge_dayjob Member, csevp Posts: 1,058 PRO

    CAD is about impossible to pick up fumbling around, like you might be able to do in a word processor. Do the training built into OS right from the source. It’s excellent and free.

  • lizardonabikelizardonabike Member Posts: 6

    @CADNurd I am planning on using the loft tool along the path of that arc. Would you still recommend adding the curves after? I have done some experimenting with the sweep tool around curves and was having bad geometry issues.

  • lizardonabikelizardonabike Member Posts: 6

    Thank you, @Matt_Shields, I see what I am missing now.

  • CADNurdCADNurd Member Posts: 64 ✭✭

    @lizardonabike - I would say that if it's something that can be done with the fillet tool then add it after. Otherwise, do whatever works to give you the exact shape you're after.

    Unemployed Onshaper - operating on European time. More of me here ➤ https://linktr.ee/Liam.G

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