- Select Window > Preferences. The Preferences dialog box is displayed.
- Select the Compatibility item in the left-hand side of the Preferences dialog box. The Compatibility panel is displayed.
- Check the 'Invert' checkbox.
Warning: Some mouse drivers or configuration utilities make it possible to map mouse buttons to various functions or keystroke assignments. You should make these kinds of changes carefully because SketchUp makes extensive use of the mouse buttons in combination with various modifier keys (Ctrl, Alt, Shift), and you could easily lose functionality by remapping the mouse buttons.