Extracting quantities directly from the model. The practical side of 5D. QTO means extracting quantities directly from the model - wall areas, duct lengths, concrete volumes, door counts - instead of measuring drawings by hand. In Revit this happens through Schedules; tools like Navisworks or Power BI let you slice quantities by level, zone or construction stage.

QTO quality depends directly on modeling quality: an element modeled wrong gets counted wrong.