Design Nomenclature / Form & Geometry
Mass
Also called visual mass, presence, weight
The perceived weight and presence of a form — how convincingly it reads as being made of something. It is a judgement, not a measurement: a hollow shell and a solid billet with the same silhouette enclose the same volume and carry different mass, and the difference is section thickness, radius size, and how light turns the corners.
In practice
Industrial designers say a form 'has mass' or 'reads light' about proportion and surfacing, never about kilograms. Distinct from the physical quantity and from volume, which is arithmetic.