# Rotation relative to custom axis

hi there,

Ive been working hard to do some basic things in rhino that don’t seem to be possible in any easy way. One of those things is this:
I want to rotate an object according to a diagonal plane but the 2d rotation tool only allows rotation according to a plane, right? Is there no other work away? It would be such a useful tool.

To explain what I want to do a video is more useful than words so firstly: https://youtu.be/NU230z_o5aI

Basically I want to rotate the equilateral pyramid to be (roughly) in the position I show in the video, albeit with the line that I trace being straight. Than I show how obviously rotating the object from the one point to the other point with the 2d rotation tool doesn’t work because the tool doesn’t detect the plane but defaults to a given plane limited to absolute planes.

The only way I can think of to accomplish this is by setting an exact rotation degree either with the rotate tool or the gumball, which isn’t so difficult, but I stumble against this same issue so many times that it felt valuable to see if someone has a better way.

Might as well ask a second thing: Perfect Pyramid (3 and 4 sided) in Sketchup - YouTube Is there any similar tool to the eraser tool in sketchup shown in this video. In order to make the shape I just used the edges I established using this method and manually created surfaces using the “surface from 3 or 4 corner points tool”, but it seemed unnecessarily tedious.

Thank you so much for your time, I hope someone can help me

check out:
_rotate3d
wich will allow you to define an axis as you like.
there is also another great tool, to do any kind of transformation / translation:
_orient3Pt

most commands belong to a category - in this case “transform”
http://docs.mcneel.com/rhino/7/help/en-us/index.htm#seealso/sak_transform.htm

so if there is a command that nearly matches your needs, you might want to check the help, and at the bottom you will find the category and / or similar commands.

the perfect pyramid in your video is a tetraeder.
rhino has a command _pyramid
and for all kinds of polyedra rhere is a plug-in

hope that helps, kind regars, -tom