When Should You Use Blocks, XREFs, and Overlays in Large CAD Projects?

[indiancad]

In larger CAD projects, performance and drawing organization often depend more on how external content is structured than on the number of objects in the drawing.

Consider a typical building project where the architectural, structural, electrical, and mechanical teams are working on separate DWG files. The architectural floor plan is referenced into the MEP drawings, structural backgrounds are updated regularly, and several common elements such as title blocks, grids, and standard details are reused across multiple sheets.

As the project progresses, revisions can quickly lead to multiple levels of XREFs and nested references. At that point, the choice between a block, XREF Attachment, or XREF Overlay can have a noticeable impact on coordination, file dependencies, and drawing performance.

I’m interested in how experienced CAD users approach this in real projects:

For a large multi-discipline project, what is your preferred strategy for keeping the drawing structure predictable, maintainable, and easy to troubleshoot as the project evolves?