SketchUp runs on Ubuntu (or other Linux OS) in Wine, and it works only because Wine simulates Windows as much as possible. Because of that, everything is analogue to Windows.
You find the SketchUp folder in
~/.wine/dosdevices/c:/Program Files/Google/Google SketchUp 8/
Components:
~/.wine/dosdevices/c:/Program Files/Google/Google SketchUp 8/Components
Styles:
~/.wine/dosdevices/c:/Program Files/Google/Google SketchUp 8/Styles
Plugins:
~/.wine/dosdevices/c:/Program Files/Google/Google SketchUp 8/Plugins
( ~ is your user profile, .wine is a hidden folder containing a "virtual" Windows environment. It's also called Wine prefix or "Wine bottle", and if several windows programs don't like each other, you can create such a "wine bottle" for each of them.)
Note that sketchy styles seem not to work for anyone. In most cases, when an application (1) in Wine wants to communicate with another application (2), you have to install the Windows version of that second application, too. For example: SU7 + Google Earth (windows).
But it's possible to use SketchUp (windows) with Gimp (linux version).