The DDL generated by Windchill defines the BLOB columns to be stored in their own tablespace. This can be controlled for each attribute by changing the tablespace property under the Windchill tab while modeling. The tablespace must be defined before the DDL is executed. The name of the default tablespace to contain BLOBs can be modified using a property in the user.properties file. See the properties.html file for details on the specific property.