The area of geometry that involves 3d objects.

That portion of geometry dealing with solids, as opposed to plane geometry.

(n) The geometry of 3-D objects, such as cylinders, cubes, and spheres, and their relationships.

Solid Geometry is a film starring Ewan Mc Gregor and Ruth Millar, directed by Denis Lawson and based on a short story by Ian Mc Ewan. Phil (McGregor) is a successful advertising executive and Maisie (Millar) is his young and hedonistic wife, but their lives are thrown into turmoil when Phil inherits his great-great grandfather's secret diaries. He becomes obsessed with research into solid geometry contained in the diaries and is fascinated by the theory of "a plane without a surface."