How do I restrict the ability to view or update materials by the material type?

Materials are assigned to Material Types and Material Types can be used to provide another level of restriction over and above organisational levels associated with Materials.

Authorisation Object M_MATE_MAR (Material Type) allows restriction by authorisation groups assigned to Material Types.

Transaction code OMS2 is used to assign authorisation groups to Material Types and these groups are entered into M_MATE_MAR to give the required access.

As with most of the implementations of the Authorisation Group concept, if there is no Authorisation Group, the check will not be performed for the Authorisation Object.