Version history in ACC lists what was uploaded. It does not tell you what is different inside the file.
Choose the pair
Rather than comparing only against the previous upload, you choose the baseline and the target. Compare the current model against the version issued for tender, or against the one the last cost plan was built on. The comparison is scoped to exactly the question you are asking.
Change, separated by type
Elements are reported as added, removed, or modified, with modification broken into whether the properties, the geometry, or the transform changed. Bounding boxes for both sides come through, so you can measure movement rather than just flag it.
Property-level before and after
Every changed property is reported with its section, name, old value, new value, data type, and unit, plus a numeric delta where one can be computed. A change report can answer “how much area was added on level 3” and not only “level 3 changed”.
In three dimensions
The 3D version comparison page renders the change set in the model, colour coded by status. Added, removed, and modified elements are visible in place, which is considerably faster than reading a table of element IDs.
Computed server-side
Comparison datasets are materialised as Parquet artifacts before the report opens. The template does not compute the diff when you open it, so a large comparison loads at the same speed as a small one.