I just discovered the command "Plan and used it to set the view to split an object. Worked great. However, I can find how to restore the view?
Assuming Rhino for Windows, press and hold Ctrl+Shift, and tap an arrow key.
You’ll probably need to change the Viewport projection back to Perspective if you used Plan in the Perspective view.
The SetView flyout in the Viewport settings can be used as well. Remember you can set a view and a cplane for any viewport and both can be changed in the respective settings for each viewport.
And, assuming for Mac, please?!
CMD + Shift and rotate the view.