joint axis and animation

can anyone tell me what a joint axis is.. and how can i animate my project which deals with gears in mesh....any reply will be appriciated

Sounds like you're trying to make a mechanism ('Applications>Mechanism') and get your mechanism to run with its own "motors", some kind of driving actuator. Joint axes can act as or be assigned such a driving property in Mechanism. All that's required is that the gears have partial constraints (be packaged - unckeck 'Allow Assumptions') and have the normal constraints converted to mechanism constraints (icon on the interface). So, for example, axis alignment (or Insert) plus two planes perpendicular to the axis aligned converts nicely to a Mechanism Pin joint axis. Then, with 'Applications>Mechanism', you take to gears and make them a 'gear pair' (there's an icon for this). The movement of a gear pair is not based on meshing but up setting up a ratio between driver and driven gear. Then a motor is assigned to the joint axis of the driver (there's an icon for this as well.). Then you run a simulation using the motor properties, save this, and run it as an animation and capture the results in an mpeg. BTW, the application called Animation, though working in a different way and producing different results from Mechanism, would probably depend setting up a Mechanism gear pair to simulate them rolling together.

David Janes