Cplane, 2 points and perpendicular to surface?

Rhino Rhino for Windows
1

is this possible? can’t seem to think my way out of this. thanks

2

Should be possible - CPlane > Object first, then CPlane > 3 pts, snap two of them and use elevator mode for the perp one.

-Pascal

3

i’ll give it a go, that sounds good. thanks