ESAComp is a software package for the analysis and design of composite laminates and laminated structural elements. The development was initiated by ESA, who envisaged open software that would combine the required composites analysis and design capabilities under a unified user interface. ESAComp version 1.0 was released in 1998. Although it originated in the aerospace field, ESAComp has been developed as a general tool for people dealing with composites in industry and in research. The latest 4.1 release features a new 3D viewer for plates and cylinders.