The 11 system variables listed in the Factors topic contain important MAXScript values.
Boolean values, the results of comparisons and state tests.
Synonyms for true and false, sometimes easier to read in state accesses.
The initial value of all variables and array elements. MAXScript generates an error if you try to perform any operation on the undefined value, except for checking to see if some value is equal to it or not:
if a == undefined then print "oh, oh"
The initial value of all keyword function arguments. Keyword arguments are optional arguments to functions. If they are not supplied by the function caller or if their function definition does not specify a default value, MAXScript initializes them to unsupplied. You can test for this value to see whether a caller has supplied a particular keyword. For more details, see the Function Calls topic.
The standard mathematical constants.
3D point values that define normal vectors for the 3 major axes. They are equivalent to [1, 0, 0], [0, 1, 0], and [0, 0, 1], respectively.