Soft seat upholstery for example may reduce the height sitting of the seated person according to how far they sink into the seat. All height dimensions relative to the seat surface (eye height sitting, shoulder height sitting, upward reach sitting) are thereby reduced accordingly.
Lateral constraints upon the actual space requirement (e.g. an excessively low seat width) may lead to deformation of soft tissue (in this case on the thigh). While still possible, sitting is then uncomfortable; the soft tissue of the thigh would increase the value for the thigh breadth.