For Gmax:

For Gmax, it is evolving today ? can you use it for your own commercial work ?
No, and No.

That point , specifying you can't use it for commercial is what makes me not trying it ! Even having to register prooves
it's not free at all to use for nay purpose like Blender.

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Yep in Blender 2.5 in any menu you display, just right click
with CTRL key (or Shift?? ?Don't remember) to define a key attached to an action.