All these types of transformation automatically take into account any 
mirroring that may occur, provided that more than two control points are 
given. 
4 Program control and data input 
  
The user communicates with the program as required either by using the 
command language or a menu technique. For this purpose, SORA-MP uses the 
DRE-X (Directive Recognition -X) software package for universal appli- 
cations. The user can switch from command input to menu input and vice 
versa. This flexibility provides the user with detailed information on 
the input possibilities at any time. 
Further, a menu user can change quickly from one menu level to another 
by using the command language, without having to go back through conse- 
cutive menus. This is particularly useful where data transfer is slow. 
The command language is easy to learn, since the currently valid commands 
are listed in the menu table. If required, a summary in command form can 
be obtained following menu input, thus providing further help in learning 
the commands. 
The following are the main features of DRE-X: 
Fast input by commands in abridged form for advanced users 
Input by command language also in batch operation and interactively 
where data transfer is slow 
Input with explanatory information in menu mode for unskilled or 
infrequent program users 
Menu mode useful for complex problems as a help to careful 
construction of input 
Data editing possible in menu operation 
Switchover possible from command to menu operation 
Largely independent of computer-specific limitations 
5 Data editing 
Control-point and other data specifying the limiting and orientation 
points can be edited as required, either formatted via files or by direct 
tabulated input in menu mode. The standard basic editing functions 
(delete, insert, replace) are available. Command language can also of 
course be used for data input, but in this mode editing is not possible.