To add a material or change the property of one (such as an experimental alloy), you would load a separate material database file. Any such file you load must be named props.dbs in order for STAR-CCM+ to use its contents. Hence, if you load more than one, they all must have the same name, so you need to create a separate directory for each one. In addition to the file(s) you specify, STAR-CCM+ loads the supplied material database by default. STAR-CCM+ combines information from multiple database files seamlessly in the simulation without modifying the database files themselves.