Sections, unfoldings, and frameworks

In solid geometry, a section is the intersection of a solid with a plane, producing a 2D shape. An unfolding (or net) is a 2D figure formed by cutting along certain edges of a polyhedron and laying it flat without overlaps. A framework (or skeleton) consists of the vertices and edges of a polyhedron, ignoring its faces.

Important properties

• The shape of a section depends on the orientation and position of the cutting plane.

• Every polyhedron has at least one net (unfolding), but not all unfoldings are nets (some may overlap).

• Frameworks help visualize the structure and rigidity of solids.