Trying to get a dimension on an edge but nothing I use actually does the job. Could you advise please?

I think you want the Aligned dimension instead of the Horizontal or Vertical tool.

I got lucky the first time out with making a tetrahedron. Now it seems undoable. The steps I’m taking are to choose the polygon from center point tool to form an equilateral triangle and then use the extrude to point tool to bring it up. What I’d like to be able to do is specify the edge length so that the solid will consist of 4 equilateral triangles. Is there a tutorial that might give me some guidance on this?

Find the intersection.

Thanks, but I can’t see what tools you’re using.

Raises again.
There are no tools that would be used.
And the difference with Mac for Windows, which could …
Ah … I’m sorry, my English sucks.(Translator …)

A little construction geometry can help… The following is done in Windows Rhino, but all the commands are available on the Mac side.


That vid was very nicely done - clear and simple. Thanks Mitch, and thanks chips also for pitching in - I quite appreciate the effort you took on my account.


Just to add another option to the mix - a regular tetrahedron can be formed from the diagonals of a cube:

1 Like

What am I doing wrong here?

You don’t have “intersection” osnap checked… --Mitch