Evans and Sutherland also developed CDRS (Conceptual Design and Rendering System) which was later bought by PTC and developed into ISDX. This is a 3D CAD tool for high quality surfacing used by industrial designers and surfacing experts to develop exteriors for automotive and consumer products. It was originally written in Lisp.
Unlike many other CAD tools, especially for its time, it described the relation between surfaces as a bunch of rules. So surfaces 'A' and 'B' could influence 'C', and then the user change their mind and decide that 'C' should drive 'A' and 'B' instead. Unlike other parametric tools which would come later, you didn't set this up by reordering a bunch of features, you just changed the connection icons between the surfaces. It was up to CDRS to figure out what order to solve the constraints and build the surfaces.
Unlike many other CAD tools, especially for its time, it described the relation between surfaces as a bunch of rules. So surfaces 'A' and 'B' could influence 'C', and then the user change their mind and decide that 'C' should drive 'A' and 'B' instead. Unlike other parametric tools which would come later, you didn't set this up by reordering a bunch of features, you just changed the connection icons between the surfaces. It was up to CDRS to figure out what order to solve the constraints and build the surfaces.