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Loft Issue

michael_fullermichael_fuller Member Posts: 27 ✭✭
edited August 2024 in Using Onshape
Bare with me.  I'm struggling to loft between a couple of adjacent shapes, closing the gap between the white shape and the orange shape and blending it to the light blue:


I'm using two sketches and a edge (the curve) as the guide



And I get this result, which is actually fine.  But...



Hiding some of the adjacent shapes, and then looking at the "back side"...



I see this.  This "ripple" causes issues when booleaning/union everything together as I then run into the ole "non-manifold body" failure.  But regardless of that, it isn't right and I want to correct it, and I'm fairly sure when I do the other issue will go away.



So I went in and thought, oh, easy fix, just sort out the connections as clearly there's some confusion...


But when I select the related vertices, the loft fails.  


So I'm clearly missing something.

Comments

  • robert_scott_jr_robert_scott_jr_ Member Posts: 525 ✭✭✭
    I seldom work with surfaces so I'm unsure if it can be applied in your case, but there is a Face Blend tool that may be of use. - Scotty
  • michael_fullermichael_fuller Member Posts: 27 ✭✭
    robert_scott_jr_ said:
    I seldom work with surfaces so I'm unsure if it can be applied in your case, but there is a Face Blend tool that may be of use. - Scotty
    I'm working exclusivly with solids, I've yet to broach surfacing.
  • Urs_Egger_REACTUrs_Egger_REACT Member Posts: 100 PRO
    That's a common issue with most CAD systems due mathematical "overshoot" of spline curves. This usually happens when you try to create a surface with only 3 edges instead of 4. So the mesh with x and y oriented curves gets wrinkled. 
    Best way is to avoid 3 sided surfaces. Or you can try to use other surfacing tools as for example "fill"
    https://cad.onshape.com/help/Content/fill.htm?cshid=fill
  • michael_fullermichael_fuller Member Posts: 27 ✭✭
    Urs_Egger_REACT said:
    That's a common issue with most CAD systems due mathematical "overshoot" of spline curves. This usually happens when you try to create a surface with only 3 edges instead of 4. So the mesh with x and y oriented curves gets wrinkled. 
    Best way is to avoid 3 sided surfaces. Or you can try to use other surfacing tools as for example "fill"
    https://cad.onshape.com/help/Content/fill.htm?cshid=fill
    Tried that; works great.  But...that creates a surface, not a solid.  How do I "solidify" that?  Getting somewhere inasmuch as that's a feature I've never tried...
  • michael_fullermichael_fuller Member Posts: 27 ✭✭
    michael_fuller said:
    Urs_Egger_REACT said:
    That's a common issue with most CAD systems due mathematical "overshoot" of spline curves. This usually happens when you try to create a surface with only 3 edges instead of 4. So the mesh with x and y oriented curves gets wrinkled. 
    Best way is to avoid 3 sided surfaces. Or you can try to use other surfacing tools as for example "fill"
    https://cad.onshape.com/help/Content/fill.htm?cshid=fill
    Tried that; works great.  But...that creates a surface, not a solid.  How do I "solidify" that?  Getting somewhere inasmuch as that's a feature I've never tried...
    Thicken!
  • S1monS1mon Member Posts: 3,146 PRO
    @michael_fuller
    Part of the challenge here is that you're trying to make a three-sided surface. Think of NURBs surfaces like a rectangular sheet of rubber or a wire mesh. They don't like to have one side be squished to zero. As @Urs_Egger_REACT said, fill may be a good option as it overbuilds the surface in a regular 4-sided way and then trims it to 3-sided. The other solution, if your design allows, is to change the corner so it has a small fourth side.



  • jaka_basejjaka_basej Member Posts: 3 ✭
    Urs_Egger_REACT said:
    That's a common issue with most CAD systems due mathematical "overshoot" of spline curves. This usually happens when you try to create a surface with only 3 edges instead of 4. So the mesh with x and y oriented curves gets wrinkled. 
    Best way is to avoid 3 sided surfaces. Or you can try to use other surfacing tools as for example "fill"
    https://cad.onshape.com/help/Content/fill.htm?cshid=fill
    yeah its indeed common issue
  • jaka_basejjaka_basej Member Posts: 3 ✭
    Urs_Egger_REACT said:
    That's a common issue with most CAD systems due mathematical "overshoot" of spline curves. This usually happens when you try to create a surface with only 3 edges instead of 4. So the mesh with x and y oriented curves gets wrinkled. 
    Best way is to avoid 3 sided surfaces. Or you can try to use other surfacing tools as for example "fill"
    https://cad.onshape.com/help/Content/fill.htm?cshid=fill
    yeah its indeed common issue
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