1) Space frames are 3D structures composed of linear elements arranged to transfer loads and form flat or curved surfaces without interior columns, creating large open areas. 2) Space frames were independently developed in the early 1900s and 1950s and became popular in the 1960s for unstable soil conditions, forming monolithic walls without cracking. 3) Space frames are designed using a rigidity matrix that simplifies calculations if joints are sufficiently rigid, neglecting angular deflections. They can be single, double, or triple layered grids and are commonly made of steel, timber, tubes, and connectors.