In general, indices in MAXScript are 1-based.
Functions expecting a 1-based index will specify this as <index>
in the function definition.
For example,
<string>getName <index>listIndex
<index>listIndex:
The index of the item for which to get the name.
In the cases where a function requires a 0-based argument, it will be specified as <integer>
instead.
Usually, the fact that the argument is expected as 0-based will also be noted explicitly in the description of the function.
For example,
<maxObject>GetRenderElement <integer>index
Returns a specific element, index is 0 based.