[Andy]

Lisa beat me to it

Here's a sample script which makes 10 cubes and positions them in a line.

set c [ac3d list]

set x 0.0
for { set i 1 } { $i <= 10 } { incr i } {
    set ob [ac3d new_cube]
    ac3d object_select $ob
    ac3d scale 0.2 0.2 0.2
    ac3d move_to $x 0 0
    ac3d clear_selection
    set x [expr $x + 0.3]
}

Here is some code to display all the AC3D internal script commands:

toplevel .test
text .test.t
.test.t insert end $c
pack .test.t -fill both

If you put either of these in a file called something.tcl in the scripts folder, AC3D will run the script when it starts. You could also send the commands to AC3D as Lisa mentions.