SAP Requirement Type and Requirement Class determination

Generally speaking we are aware that SAP Make-to-order production is controlled by the requirements type, but what’s mystical in how the requirement type is determined during the sales order processing. I did a little research to understand this process, which seems tricky compared to the some other SD area determination process like item category or schedule line and below are my findings.

Until Release 3.0, the requirements type was determined on the basis of the item category. For this reason, special item categories weree used unti Release 3.0 for controlling make-to-order production. After Release 3.0 the requirements type is determined on the below sequence primarily in the configuration for Production-MRP and Sales and Distribution in secondary.

1. The Strategy group (MRP3 View) in the Material Master,
    a. A Strategy is assigned to the Strategy group, (Tcode OPPT)
    b. The requirement type is assigned to the Strategy, (Tcode OPPS) and if this fails.

2. MRP group (MRP1 View) in the material master record.
    a. If the Strategy group is not maintained in the MRP3 view, the Strategy group
        is determined based on the Plant + MRP group combination (Tcode: OPPR)
    b. Uses step 1 after step 2.b and this if this fails

3. Based on Material type (Tcode: OMIG)

4. Item category and the MRP type
    a. Determination Of Requirement Types Using Transaction (TCode OVZI)

5. Item category only.
    a. Determination Of Requirement Types Using Transaction (TCode OVZI)


Regards,
[V]