This works for me with no specific setup that I can think of, on a MacBook Pro trackpad.
- Ctrl + Cmd click ( and hold) invokes the orbit, and then moving a 2nd finger to control it.
- Adding shift to the mix for Panning in the same manner.
I have set the secondary click to a two-finger click, but turning that off has no effect on Sketchup, and zooming is inversed… On a Mac trackpad the 2-finger swipe IS the scroll-wheel, so then it is also the zoom.
This has probably been an undocumented effect that has always been there, I have never seen it referenced anywhere, but adopted it sketchupping on small cafe´ tables. The mouse would take the place where my beer was supposed to stay 
Obviously using one button at the time to alter trackpad gestures would be better than my 2 or 3-keys+ click-drag combination.