The node‑to‑node distance tool in STAAD.Pro is quite basic and, in its current form, not particularly useful when distances need to be measured independently along the X, Y, and Z axes.
Bentley already provides this functionality in some of its other products; however, it is unfortunately missing in STAAD.Pro. This appears to be an oversight rather than a technical limitation.
Please see the link below for reference. (https://docs.bentley.com/LiveContent/web/Promis.e%20Help-v9/en/MeasureDistance.html)
There should be a measure tool in which even if we measure inclined distance, it should show inclined distance as well as all 3 coordinate distances.