By John Flanagan
Introduction
During training courses, I often get asked about file sizes in Revit. There are many things to consider regarding file size - complexity of the design, size of the building, number of levels, source of the content loaded, etc. In my experience, any file size is acceptable if it still performs well. Check out Autodesk's Model Performance Technical Notes and possibly AU session AB100-1P (Managing Large Projects in Revit Architecture).
Here are some tips on how to reduce Revit file size
Warnings - These get ignored and pile up and some of these are more offensive than others. Room, space and area errors caused by boundary issues or redundancy is wasting your cpu's time. Any warning is a waste of "space" and "resources" to some degree.
View Detail - Do you have a lot of views that are using fine or medium detail level but have scales like (1:200, 1:100, 1:50)? These views won't really show this level of detail for all elements effectively and you are asking the computer to show it anyway. By predefining detail levels, you can affect the display of the same geometry at different view scales.
Unused Families – When working in a Revit project and you realise that you have loaded more families than are needed to complete the project, purge out the unused families.
Compact Central – This is like the operating system performing defragmentation of your computer's hard drive. Think of it as asking Revit to clean up after a busy day, it allows Revit to reduce file size.
Create New Central File - Open the Central file with the “detach from Central” box checked and then save as a new Central file with a different file name, or to a different location on their server. This rewrites the database associated with the file and can dramatically reduce the file size.
Audit your Families – You can check the file size of your families simply by “export family types” then going through the family list to check the file size. You’ll easily be able to spot large family files at a glance.
Limit custom crop regions – Custom crop regions are “resource intense”. Limiting the number of custom crop regions will shrink file size.
Limit 3D views – Keep the number of 3D views in your project to a minimum. Similar to custom crop regions, 3D views are “resource intense”.
Limit imported images – Reduce the image file size by as much as possible without compromising the quality of the image.
Export Renderings and walk-through’s – Any renderings or walkthroughs created in Revit increase your file size, by exporting these you can dramatically reduce the file size.
Limit the use of Groups and Array’s – Large numbers of groups and array’s in a project can slow the model. Purge unused groups from the model often and turn off “Group and Associate” when using the Array tool.