When you start Softimage for the first time, you are prompted to choose an interaction mode for mouse and keyboard actions. You can change the interaction mode at any time.
The different interaction mode set a variety of preferences, including which parameters are keyed by default. It is strongly recommended that you do not switch between modes while working because you might not actually be keying the parameters that you think you are keying.
For more information, see Selecting Which Keying Method to Use [Animation].
If your version of Softimage is part of an Autodesk suite, you can also choose which components will use this interaction mode from the right drop-down box.
It is recommended that you choose the Softimage interaction mode because it is optimized for use with all Softimage tools. In particular, it makes the most efficient use of modifier keys like Shift, Ctrl, and Alt.
If you prefer to use the Alt key for camera navigation, you can set Use Alt key for view navigation in your Tools 
Camera preferences (File Preferences). You can also set Mouse Mapping to Maya to use the left mouse button to orbit, the middle mouse button to pan, and the right mouse button to zoom.
If you are familiar with SOFTIMAGE|3D, you may be more comfortable either Softimage with Extended Component Selection or SI|3D. Both of these interaction modes mimic the selection methods used in SOFTIMAGE|3D. Other users will probably not find these modes intuitive.
If you are familiar with other 3D software, you may be more comfortable with either the Maya or the 3ds Max interaction modes.
