Applications of Euclidean constructions to computer graphics (Q1118338)

The paper presents an interactive graphics system (called LEGO) which is able to model 2D and 3D objects using Euclidean geometry constructions. This system is designed using the layered approach. The IRIS Graphics Library is the bottom layer in the current implementation. C-LEGO is the level 1 and is a library of C functions with which the user can specify objects in terms of Euclidean geometry. The programs using C-LEGO functions must be compiled. A LISP interface for C-LEGO forms the level 2 (LISP-LEGO). The programs can be constructed interactively, while the functions can be defined interactively and used at the same session without compiling. It is not required to define objects prior to their use. The level 3 is a visual interface and allows to construct LISP-LEGO programs. The graphical interface can be used concurrently with the textual interface (LISP-LEGO) and the type of interface may be changed even when specifying a single statement. Some applications, such as the teaching of Euclidean geometry, the analysis of mechanisms, modelling of curved surfaces, are also presented.