Having established CAD Standards with your level libraries it is useful to keep project data synchronised with those libraries.
But....you do need to control what is synchronised!
There are a group of configuration variables that control level synchronisation and editing abilities.
Default level symbology attributes are generally set ByLevel in level dgnlib libraries. Individual users usually need to be able to modify some of these attributes, generally the override symbology.
The following variable settings allow users to modify override symbology while keeping other attributes in sync with the libraries.
1. MS_LEVEL_EDIT_ATTRIBUTE_LIST = OverrideSymbology
sets the attributes that can be edited, in this case all the Override Symbology attributes. Note that the OverrideSymbology value applies to all override attributes, separate values are available for individual override attributes if required.
2. MS_LEVEL_AUTO_SYNC_ATTRIBUTE_LIST = ByLevelSymbology,DisplayPriority,Transparency,Lock,plot
sets the automatic sync then lists the attributes that will be updated.
To maintain standards levels in active files need to be synchronised with the library automatically, obviously the overrides set by the users need to be left alone so this synchronises the attributes listed but not the overrides.
3. MS_LEVEL_SYNC_ATTRIBUTE_LIST = ByLevelSymbology,DisplayPriority,Transparency,Lock,plot
operates when a key-in command is used to update levels, this is also needed even where the automatic sync is in place, both should be set to the same values otherwise a manual update could change a different range of attributes.
4. MS_REF_REATTACH_LEVEL_SYNC_ATTRIBUTE_LIST = ByLevelSymbology,DisplayPriority,Transparency,Lock,plot
controls the list of level-attributes that will sync-up when a reference is reattached, and generally should also match the previous two.
To allow override symbology to be edited before an element is placed on a level include:
MS_LEVEL_ALLOW_LIBRARY_LEVEL_EDIT = 1
On editing, the library level will be copied into the active file.
To allow the editing of Override Symbology on nested reference files:
MS_LEVEL_EDIT_NESTED_ATTACHMENT_LEVELS = 1
also see help topic "Performing Operations Across DGNs and Levels"
Be aware that applying these settings to existing data can affect their appearance!
I recommend applying these settings only to new projects via the PCF.
Project teams will need to be briefed on the synchronisation behaviour and the need to make symbology changes only to level overrides to avoid frustration.
More details regarding these variables can be found in the help documentation and also in this wiki: Overriding And Resynchronizing Level Attributes
Level synchronisation was not automatically available in V8i applications. To enable level library synchronisation for V8i set:
MS_DGNAPPS > synchbylevel
This adds synchbylevel.ma to the MDL applications loaded at start up (synchbylevel.ma is located in C:\Program Files (x86)\Bentley\....\mdlsys\asneeded).
synchbylevel is replaced by MS_LEVEL_SYNCH_BYLEVEL variable for CONNECT edition