There's no orbit in perspective.
You can use fly mode (press F I think), and then fly around the model. Shift should speed up movement.
But I agree that the mobile/tablet app is more intuitive and has better features, which is why I haven't used the desktop app in ages. It also suffers from 'flickering' when exploring. I think the engine used hasn't been updated in many years. It was great back in 2006/2007 though, when we first got Virtual Building Explorer (I think).
Erwin Edel, Project Lead, Leloup Architecten
www.leloup.nlArchiCAD 9-26NED FULL
Windows 10 Pro
Adobe Design Premium CS5