You typically use the OPTEX procedure to create an output data set that contains the design for your experiment. If you use an OUTPUT statement, the variables in the output data set are the factors of the design as well as any ID variables. The values for the ID variables are taken from the input data set (the DATA=, AUGMENT=, or INITDESIGN= data set) that provided the design point. ID variables must be contained in the DATA= data set and can also be contained in the AUGMENT= or INITDESIGN= data set. If an AUGMENT= or INITDESIGN= data set does not contain the ID variables, and points from the data set are used in the final design, values of ID variables for those points are missing.
Since the input data sets provide candidate points for the design, all the observations in the OUT= data set originate in one of the input data sets. The OPTEX procedure does not change the values of variables in the input data sets.
Since you can use multiple OUTPUT statements with the OPTEX procedure, you can create multiple OUT= data sets in a given run of the procedure.