I know someone who's working on a 3dsmax project using 3.1

I have 3.0 but not 3.1

is 3.1 a free update? I can't find it anywhere on discreet's site anywhere or even that 3.0 once existed (all patches and updates are for 3.1)

I know kinetix used to own 3dsmax - is it even posible to get 3.1 anymore without having to buy it?

Max R3.1 is/was a free service fix that went out to all registered owners of R3 and distributed with all new copies of Max that were purchased.

If you legally own R3.1 then you can contact your dealer, reseller, or possible even Discreet in order to get your copy. There is no download of R3.1

You should still be able to open a R3.1 file in R3, just as you can open any R4.x compatible file in any version of R4.x