This video explains how SOLIDWORKS calculates and displays mass properties under the Evaluate tab. It covers default density settings, automatic calculations for mass, volume, surface area, centre of mass, and moments of inertia. Accurate results require assigning real materials, adjusting units and precision, and optionally increasing accuracy for large assemblies. Users can override calculated mass, change datum points, and select individual bodies for specific data. The centre of mass can be represented as an updating feature, and properties can link to custom attributes for BOMs and drawings. These tools help create realistic models and ensure accurate physical data for design.