Since graduating from Cambridge University in 1960 Charles has spent most of his career working in the field of computational geometry, computer graphics and computer-aided design (CAD). After returning from two years at the Massachusetts Institute of Technology in 1965, he founded the CAD Group at the Cambridge University Computer Laboratory before jointly founding Shape Data Ltd in 1974 and Three-Space Ltd in 1986. Both these Cambridge companies specialised in 3D geometric computation and its application. The 3D geometric modellers they developed are used in CAD systems worldwide.
More recently Charles has been taking an active interest in problems arising from climate change, and in particular issues relating to global food security. He is using his experience to encourage and support entrepreneurship in agriculture and associated industries.