Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape.

First time visiting? Here are some places to start:
  1. Looking for a certain topic? Check out the categories filter or use Search (upper right).
  2. Need support? Ask a question to our Community Support category.
  3. Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
  4. Be respectful, on topic and if you see a problem, Flag it.

If you would like to contact our Community Manager personally, feel free to send a private message or an email.

Newbie question - how to make a solid icosahedron?

phillip_wrightphillip_wright Member Posts: 2
Hi all,

I'm just learning CAD. I have a pretty simple problem, but it seems to be beyond me in OnShape.

I'm want to create a solid icosahedron. I've tried a few different approaches, but I feel like everything I do gets messy and tangled up.

I've seen some tutorials for SketchUp and Solidworks using 3d sketching approaches, but that doesn't seem to be how things are done in OnShape. I guess I'm looking for a solution based on 2d sketches and extrusion? (again, new to CAD so not really sure).

Thanks in advance.

Best Answer

Answers

  • phillip_wrightphillip_wright Member Posts: 2
    Great - thanks Andrew.

    I ended up using "loft" to raise the pentagon to a point (because I'm able to define the height of the apex point in terms of the side-length of the pentagon). I hope that's an appropriate use of loft.

    A like the idea of the extruding the triangles to the interior and then boolean-ing them to neaten it up, as well as using circular rotate - awesome.

    I'm glad you mentioned things like "Onshape cannot yet create a planar surface from a sketch", and confirming that 3d sketching is not currently possible. Saves me from worrying about whether I'm missing something.

    Thanks again,
    Phil
  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭✭

    @phillip_wright - Nice enhancement using loft. My method relied on knowing the angle analogous to the pitch of a roof - I infer that must be a constant for all regular icosahedrons (although I have no idea what it is) ... but it's nicer to come up with methods which derive all their variables from sketch geometry, and loft is a great way to do that (and neater than my kludge, to boot)


  • andrew_troupandrew_troup Member, Mentor Posts: 1,584 ✭✭✭✭✭
    Onshape does not (on the 'face' of it) have a way of creating a plane which contains a specified line and point, which is needed for constructing the 'lattice' triangles, but (except to someone used to having that option), it's probably obvious that the user can easily pick the endpoints of the line, in order to instead use the "three points" option for the plane.
Sign In or Register to comment.