for your first question, if you aer using Non-sequental Mode then you could find MEMs directly under the NS object list, The DLL version is used in sequential mode alone! ^)TZHc2a[
af)L+%Q%R
For your 2nd Q, like the upstairs's reply, the STEP files should be saved under ZEMAX\Objects\CAD Files. >HyZ~M
U 1vZr{\
Hope this would help :)