We've found that files are slow to load as we open each drawing which is impacting productivity in our office. We also experience some lag when navigating around our drawings, whether in the Drawing/Sheet model or when a Drawing View is applied to the 3D model. We're at a stage in our project where caching our drawings is not practical, so we're not sure what else we can try.
There are a number of factors that may be involved, so the suggestions below address potential methods for improvement in many different areas.
1) If you are getting Visibility Calculator messages in the MicroStation Message Center, choose Building Designer > Enable Auto Annotations and uncheck this option. This process scans drawings to determine the current element display state, so that drawing annotation is automatically generated when the display of an annotatable component has changed. By disabling it, you should be able to alleviate the Visibility Calculator portion of the load time which is often a significant portion. Once re-enabled, simply reopening the Drawing Model will display all annotation changes since the option was disabled. What you can do is to leave this option disabled for day-to-day work, and enable it only when you need annotation to be updated.
2) Temporarily turn Unification off by choosing Building Designer > Enable Unification. The unification cache is stored in drawing views and this tends to make the file size larger, so if compress your files on a regular basis it will remove all unification cache and enhancements that are designed to speed the opening of the file. The next time the model is opened it will take a longer period of time to create the unification cache and speed enhancements again.
3) Avoid "circular referencing" by making sure that there are no duplicate references via Live Nesting. We have encountered scenarios where the same elements were being duplicated multiple times due to the structure of the attached references, which in turn will use much more memory without any benefit since each "duplicate" instance of an element occupies the same physical space.
4) Acceleration in Dynamics determines whether Part attributes (e.g. rendering, unification and resymbolization) are included in view navigation and dynamics. For larger and more complex models, you may want to accelerate their dynamics by moving to Low or High.
BB_ACCELERATE_DYNAMICS = NONE, LOW or HIGH
None (Default) - Part attributes are displayed during all view navigation and dynamics.Low - To accelerate display performance, Part attributes are not displayed during all view navigation and dynamics in the context of Dynamic viewsHigh - To further accelerate display performance , Part attributes are not displayed during all view navigation and dynamics
5) Using ProjectWise may help, particularly in a Managed or Hybrid Workspace environment, since all files will be cached locally thereby removing any potential network bandwidth limitations.