Preferred property values are dynamically saved as defaults at the time of placement from within the Property Panel. The new default dimensions are then used on all subsequent routing operations. The menu option Set as Default AutoFitting option appears on all components included in Mechanical discipline's auto-fitting placement functionality. Transitions, elbows, takeoffs and all variations within those item types (mitered elbows, radius takeoff or angled takeoff) are affected. Right clicking on this option sets the default components for auto-placement during routing operations. When the menu option is selected, the component's current instance data is stored in the preference file bmautoinstancedataprefs.xml. The AutoFittingOptions.xml is also modified to store the updated default auto-placement instance data.