Problems with tangency constraints on a fill feature

ronny_brekke
ronny_brekke Member Posts: 5 ✭
in Community Support
I'm pretty new to onshape, and bumps into stuff all the time. But this, I don't know what to do. I'm trying to make a car hood with an indention in it. I've made a outline surface of the hood, and I've cut out a hole where I want the indention. I've cut up the hood to make tangency patches for a fill. I'm getting a kind of result, but I get some error messages, and all though I have a solid surface I can't thicken it, as it's something wrong.

If someone could look at my model and tell me what I'm doing wrong, and how I really should do it, I would very much appreciate it. 

Onshape document

Best Answer

  • ronny_brekke
    ronny_brekke Member Posts: 5 ✭
    Answer ✓
    Thanks for your replies. The solution got to complex for me, so I did it in a simpler, less accurate way. I made a sweep along the bottom indent curve to  create a surface, and merged the two, and finally made a fillet around the edge.

    The solution, if anyone's interested.

Answers

  • S1mon
    S1mon Member Posts: 4,588 PRO
    If you don't want a crease down the middle of the indents, then the indent bottom curve needs to be at least tangent to the main hood surface, and you probably want the cutout to have rounded ends as well. You'd probably be better off making most of the surface with a loft and then using fills on the ends, with some bridging curves as guides. 

    1. Make the blue curves
    2. The red curves need to be tangent to the blue borders
    3. The orange curves probably want to be bridging curves which are curvature continuous at each end
    4. The blue part is probably a loft
    5. The ends are probably fills

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  • GregBrown
    GregBrown Member, Onshape Employees, csevp, pcbaevp Posts: 412 image
    edited September 2023
    You'll definitely struggle with the current approach for that fill, especially with the boundary conditions (tangency) you are asking it to meet. The curves as they are currently are inconsistent and cannot  solve for tangency. In fact this is a really good case to highlight a somewhat recent (1.159 from the top of my head) tool we added to measure... the "Face tangent angle".  In the image below you'll see I have selected a side edge from the "indent btm" and the surface "c2". These meet in an angle of about 11.5 deg, so the fill will not be able to be created tangent to both of these in that corner - hence the error message.

  • ronny_brekke
    ronny_brekke Member Posts: 5 ✭
    Thanks for your replies. The solution got to complex for me, so I did it in a simpler, less accurate way. I made a sweep along the bottom indent curve to  create a surface, and merged the two, and finally made a fillet around the edge.

    The solution, if anyone's interested.
  • ronny_brekke
    ronny_brekke Member Posts: 5 ✭
    Answer ✓
    Thanks for your replies. The solution got to complex for me, so I did it in a simpler, less accurate way. I made a sweep along the bottom indent curve to  create a surface, and merged the two, and finally made a fillet around the edge.

    The solution, if anyone's interested.

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