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parametric dome

ol_loool_loo Member Posts: 8
Hello,
I fail to understand how i can make a parametric domeat the extremity of a solid cylinder. For some reason the loft tool refuses to create a dome or at least all the combinations i tried failed, usually i use two spline with common center point and then the loft tool, but in onshape it doesnt work.i have to draw the profile on perpendicular plan and then use the fill tool, i end up with a surface instead of a editting my solid, so i later have to make a solid from the surface and then join the cylinder and this solid, of course the parametric control is lost at this point, so i cannot edit back the profile, which is of course problematic

Answers

  • SethFSethF Member Posts: 129 PRO
    If you could attach a document that's been made public, it might help a lot with understanding your issue.

    From your explanation, this is what it sounds like you're attempting to create, though I'm not sure how the loft comes into play.. Is this along the right lines?
  • bruce_williamsbruce_williams Member, Developers Posts: 842 PRO
    @ol_loo
    First, welcome to the forum and Onshape.  i think you will be rewarded by both!

    @sethf example doc is what I understand also and shows how you will want to use Revolve.

    In order to copy the doc - change to Main and you will get a copy button.  

    I just noticed with a link to version like Seth has, there is now copy button.  Could someone comment on this?  Seems strange we cannot copy a version directly...




    Switching to main through the version menu is necessary...


    www.accuratepattern.com
  • ol_loool_loo Member Posts: 8
    here it is an half sphere with no control. What i need is full control over both angles, and i always did it with two spline and a loft tool in others cad.
    For some reason with onshape there seems to be a bug where two identical splines drawn from the same 3 points on two diffent plans end up never intersecting in the middle. That is the reason why the loft tool doesnt work once the profiles are selected, since they dont intersect.
    Anyway, it seems the only way with this bug is to draw half the profile, with a spline, and use the contour tool, i did that and it worked fine, and doesnt brake parametric control so i can change the height and both angles at any time.
  • bruce_williamsbruce_williams Member, Developers Posts: 842 PRO
    @ol_loo
    Please help us help you - see this post on sharing a document.  https://forum.onshape.com/discussion/9107/forum-post-checklist-read-this-first#latest

    You may need to use pierce or coincident constraints.  Not sure till we see what you are doing...
    www.accuratepattern.com
  • steve_shubinsteve_shubin Member Posts: 1,066 ✭✭✭✭
    ol_loo

    Here are a couple more domes
    On the first one you could adjust by editing the sketch

    On the second part studio you can adjust by editing the variables
    But you have to use caution on this one because it will fall apart depending on the input

    https://cad.onshape.com/documents/cbf2e3e371fdd96340fc418c/w/42a992c419161113f3bff435/e/2267ba388805101ec6d09b78
  • SethFSethF Member Posts: 129 PRO
    https://cad.onshape.com/documents/7ac1b29a37ea80253a6e8c4d/v/bc1e858ad2c2dbf4e70e6079/e/cbc29190e42cadbc5573507f

    The second tab, you can still accomplish without needing to mess with Loft, if I'm correct in understanding that you're making an elliptical dome.
  • steve_shubinsteve_shubin Member Posts: 1,066 ✭✭✭✭
    edited October 2021
    SethF said:
    The second tab (Elliptic Cylinder Dome), you can still accomplish without needing to mess with Loft
    TRUE

    But loft gives an additional variable in not only being able to adjust the X and Y of the ellipse, but in addition, being able to adjust the height of the dome independently





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