VSS 2018 – Gravity and Ground Plane Geometry in Perspective Images

“The small things float to the top of… gravity” — Rickie Lee Jones

Renaissance artists noticed that placing objects on a visible ground plane anchors them stably, making it easy to perceive their depth. Subsequently, they developed methods for geometric calculation of perspective by drawing construction lines defining the ground plane. Thus, the artist constructs the geometry of pictorial space, based on the station point and the view direction, then places objects in it. This practice created a scale for placing and sizing objects on a minimally patterned ground plane.

In such paintings, feet are usually visible; our pilot experiment shows that the feet provide the viewer with an accurate perception of relative depth, configuring the scene elements into clusters. The underlying cause lies in the structure of vision, which privileges the horizontal ground and downward gravity.

FourquetPhillips 2018