even Rhino v5 or v6? thank you very much!
if you click on this icon on the right upper corner on top of your browser 
you can search the forum for what you need. this is pretty basic command
also a quick search on google provides you with all you need.
anyway here you can inform yourself on the command isometric
dim is the same for any perspective, also DimAligned if the angles are not orthogonal.