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Curve Pattern on Spiral with Orientation locked on Circle Center

SkiBoy22SkiBoy22 Member Posts: 10

I want to pattern an object along a curve (ive tried both Helix and Parametric) and lock the orientation on the center of the circle (in my case the Z Axis).

The curve starts at 120mm Radius and ends at 40mm radius

https://cad.onshape.com/documents/00c9db9d02dbafeaa5e0345b/w/500ced153d64ee09c8cacef3/e/7f5494a24f6260ffa34ba8d8?renderMode=0&uiState=68c9b5950dc5a3ffa226f524

Grey: What I get
Red: What I want

image.png

Comments

  • S1monS1mon Member Posts: 3,579 PRO

    Pattern a sketch feature which is dimensioned by the angle, and coincident with the curve, and re-apply feature.

    Simon Gatrall | Product Development Specialist | Open For Work

  • SkiBoy22SkiBoy22 Member Posts: 10

    Im not sure what you mean by dimensioned by the angle?

    I have also made all the refrences other sketches as per the curve pattern tips. It seems to work on the first and last however most of hte instances inbetween are skipped

    image.png image.png
  • SkiBoy22SkiBoy22 Member Posts: 10
  • S1monS1mon Member Posts: 3,579 PRO

    Yep. I've tried a bunch of combinations and work arounds, and I'm finding it shockingly difficult to do what you're trying to do.

    I managed to get something that 95% works. It can't handle the last member of the pattern and depending on the count, some pattern instances will flip, but for some values of #c (the count), it works:

    https://cad.onshape.com/documents/f87eec8e04343d46741dbf2c/w/9da5103c5970b339455003ea/e/1c0444aa9daa6801f2423488

    image.png

    Simon Gatrall | Product Development Specialist | Open For Work

  • EvanReeseEvanReese Member, Mentor Posts: 2,551 PRO

    ooh that's a tricky one! I tried a few things and got this working.

    https://cad.onshape.com/documents/07cc9f9029c8433d65138b5c/w/f369bd3fa338a993997075d9/e/c1c7dfefafdb8b6aa3aa9a4a

    image.png
    Evan Reese
    The Onsherpa | Reach peak Onshape productivity
    www.theonsherpa.com
  • SkiBoy22SkiBoy22 Member Posts: 10

    Thank you both! Exactly what i needed 😁did not realize you could update a variable! very cool 🤓

  • S1monS1mon Member Posts: 3,579 PRO
    edited September 18

    Yep. It's a weird - but useful - way to do a loop in Onshape. Using a pattern that actually doesn't move anything by itself, except to cycle through features including the increment variable expression.

    Simon Gatrall | Product Development Specialist | Open For Work

  • EvanReeseEvanReese Member, Mentor Posts: 2,551 PRO

    I love that technique! I noticed the last instance wasn't always working. I think it's because of a rounding error sometimes making the param go to something like 1.00000001 instead of 1 so I threw it into a min function and it's stable now

    image.png
    Evan Reese
    The Onsherpa | Reach peak Onshape productivity
    www.theonsherpa.com
  • S1monS1mon Member Posts: 3,579 PRO

    @EvanReese Wow. That kinda makes sense, but definitely a lot more hoops and insider knowledge than should be necessary to make this work.

    Simon Gatrall | Product Development Specialist | Open For Work

  • Derek_Van_Allen_BDDerek_Van_Allen_BD Member Posts: 221 PRO

    Programmer philosophy? In my mechanical CAD package? It's more likely than you think.

  • MichaelPascoeMichaelPascoe Member Posts: 2,542 PRO
    edited September 18

    Feature pattern appears to a little buggy and unpredictable ever since the pattern update a few updates back.

    You can do this with a single mate connector paired with simplified sketch constraints. But even adding something as simple as a line to centroid seems to break the feature pattern. This is a bug imo since adding a line to the sketch messes with the up-stream mate connector. I've submitted a bug report, we'll see where it goes.

    https://cad.onshape.com/documents/266599a738971262330336fc/w/8b44e6d5e12f9f9c52f2c86b/e/ab346529f8cef3047642b43…

    image.png

    Learn more about the Gospel of Christ  ( Here )

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  • EvanReeseEvanReese Member, Mentor Posts: 2,551 PRO

    This is similar to the first approach I tried and didn't like the unstable result I was getting, but I think yours works better via curve pattern. I thought about coding a feature to place mate connectors with X pointed at a chosen vertex, but it felt like overkill haha.

    Evan Reese
    The Onsherpa | Reach peak Onshape productivity
    www.theonsherpa.com
  • MichaelPascoeMichaelPascoe Member Posts: 2,542 PRO
    edited September 18

    @Konst_Sh funny, I actually tried your Multi Mate Connector in my first approach, but it wasn't pointing the correct direction. I assumed it was because of the feature pattern issues.


    Learn more about the Gospel of Christ  ( Here )

    CADSharp  -  We make custom features and integrated Onshape apps!   Learn How to FeatureScript Here 🔴
  • Konst_ShKonst_Sh Member Posts: 72 PRO

    @MichaelPascoe feature pattern is definitely weird, maybe its because it being combined with curve pattern and transform from curve makes it flipped from exact orientation though. But the parameter pattern works as expected in combination with multi mate connector.

    param pattern.png

    Another option would be to use Path pattern custom feature with orientation option - Normal and tangent - with reference cylinder face around origin

    Path pattern.png
  • EvanReeseEvanReese Member, Mentor Posts: 2,551 PRO

    @Konst_Sh that's fancy! I like that this community is so pumped about Onshape that they keep answering the question after it's been answered because we just can't turn down a CAD challenge.

    Evan Reese
    The Onsherpa | Reach peak Onshape productivity
    www.theonsherpa.com
  • S1monS1mon Member Posts: 3,579 PRO

    @EvanReese
    I enjoy this too, but I'd love to see some Onshape employees chime in. It really seems like we should be able to solve this problem without using custom features, or tricky patterns. Re-apply feature should be more robust.

    Simon Gatrall | Product Development Specialist | Open For Work

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