vertex_format_add_position_3d();
Returns: N/A
Tell GameMaker: Studio to accept 3D positional data (x, y
and z) as part of the new vertex format being created.
vertex_format_begin();
vertex_format_add_colour();
vertex_format_add_position_3d();
my_format = vertex_format_end();
The above code will create a new vertex format with just colour and position values and then store the format id in the variable "my_format".