Pattern: Fill Transient Attributes of Persistent Nodes 
You can configure determinations according to this pattern to derive the values of transient attributes of a node.
Determinations configured according to this pattern are automatically executed before the consumer accesses a transient node attribute of the corresponding node for the first time. For this reason, you can initially derive the values of the attribute. In addition, determinations of this pattern are executed after a node instance has been modified. Data of the transient field are recalculated if its derivation source attribute has been changed by the modification.
The VOLUME attribute of a specific item of the CUSTOMER_INVOICE business object can be derived out of the attributes LENGTH, WIDTH, DEPTH, and QUANTITY. The VOLUME attribute is a transient attribute of the ITEM node and its value can be derived as soon as an item is loaded from the database. Therefore, you can use a determination of this pattern that calculates a value corresponding to the VOLUME attribute when an item is loaded from the database.