Abstract : This paper presents an integrated set of tools helping to describe movements of objects in a framework of key-framed animation, both in simple and complex scenes. We want to have a powerful, robust and fast tool for designing either quickly prototyped or finely tuned motions. To achieve that, we will bring together Hermite splines (with an optional simplified interface for tangents, extended from [KB84]) and logarithms of quaternions for orientations [Han93]. We define an interface featuring both by-hand and simplified tangents edition. This gives us a unified simple interface for both translations and orientations. The construction of complex movements is easier to perform by assembling simpler ones, through hierarchy, rendezvous or links with other types of animation (dynamics, articulated structures,...) We particularly address implementation considerations, and the problems of fast computations, to get interactivity.