I've made a new scripting tutorial @http://www.isner.com/tutorials/commands\_vs...ject\_model2.htm
I've tried to show what I think is the fastest way to make custom tools in XSI and explain the differences between Commands and the Object Model. Really it is written for XSI 2.0, but the only 2.0 specific lines are getting a vector object and the description of where to look in the help.
Good stuff, keep'em coming.