Whenever you start having strange problems in Softimage, it’s a good idea to try resetting your User preferences. You can do this by renaming the default.xsipref preference file in %XSI_USERHOME%\Data\Preferences (for example, to default.xsipref.backup). The restart Softimage; that will recreate a factory-default default.xsipref file.
Tip If resetting the preferences doesn’t fix the problem, then try renaming your User folder (for example, to C:\users\blairs\Softimage_2010.backup). That will force Softimage to recreate the whole User folder. Sometimes the problem is not the preferences, but some other file or setting in the User folder.
So why does resetting the preferences fix strange problems? Usually we just assume there was a bad preference setting, or a bad combination of settings. But I’m not so sure.
The other day a customer called with a problem: he couldn’t see his blendweight fcurve in the Animation Editor. I Webex’d to his machine to check it out, but I couldn’t get it to work either: right-click the animation icon and click Animation Editor, but there’d be no fcurve. I could repro on my own machine, but my colleague Manny couldn’t repro on his. So I renamed my default.xsipref, restarted Softimage, and then I could see the blendweight fcurve. This worked for the customer too.
Later, I compared the factory-default default.xsipref with my backed-up version, and tried to reproduce the problem by hand-editing my new default.xsipref. But I couldn’t. Eventually I put back my original default.xsipref (the one I had when I could repro the problem), but even then I could not reproduce the problem.
So. Resetting the preferences fixed the odd behavior, but putting back the “corrupted” preferences file didn’t bring the odd behavior back. It seems like it is not the content of xsipref file itself, but the act of forcing Softimage back to the factory-defaults that resolves the problem.