I have a comic problem with 3ds max. I want to have a 500X500 size video from 3ds max. However 3ds max creates 720x480 size avi video.  Example: if I select 500x500 output size, when play the resulting avi, its 720x480. I really couldn’t solve the problem. Even I am typing 500x500 custom size into output size command. Am I missing a setting somewhere?  Can anyone please help me?

Which CODEC are you using? Some of them only support specific image sizes.

Also, don’t render directly to avi within Max - render to an image sequence, then turn those into an avi using either Max or another app to do so. Unless you want to keep re-rendering the whole job every time you need to make a minor change.

Max 4.2 through 2014, Composite 2014.
XP-64 (SP2).
nVidia 9800GTX+ (512MB) (Driver 314.22).
i5-3570K @ 4.4GHz, 8Gb Ram, DX9.0c.

You can use max to do that, After Effects ($$$), VirtualDub (free) - there are many.

Max 4.2 through 2014, Composite 2014.
XP-64 (SP2).
nVidia 9800GTX+ (512MB) (Driver 314.22).
i5-3570K @ 4.4GHz, 8Gb Ram, DX9.0c.

;) ok I got the my way thanks a lot..

Video Post. Create an .ifl for the files (Utilities > More > IFL manager). In VP create an image input event and pick the ifl file. Create an output event. Process.

More details in the Max Help.

Max 4.2 through 2014, Composite 2014.
XP-64 (SP2).
nVidia 9800GTX+ (512MB) (Driver 314.22).
i5-3570K @ 4.4GHz, 8Gb Ram, DX9.0c.