Deformations are a powerful tool for shape modeling and design. We present a new model for producing controlled spatial deformations, which we term Simple Constrained Deformations (Scodef) . The user defines a set of constraint points, giving a desired displacement and radius of influence for each. Each constraint point determines a local B-spline basis function centered at the constraint point, falling to zero for points beyond the radius. The deformed image of any point in space is a blend of these basis functions, using a projection matrix computed to satisfy the constraints. The deformation operates on the whole space regardless of the representation of the objects embedded inside the space. The constraints directly influence the final shape of the deformed objects, and this shape can be fine-tuned by adjusting the radius of influence of each constraint point. The computations required by the technique can be done very efficiently, and real-time interactive deformation editing on current workstations is possible.

The paper deals with the problem of the multiple solutions of the coordinate transformations for an n-link robot manipulator. Aspect decomposition of the admissible domain of the joint space is introduced and an algorithm for automatic computation of Aspect decomposition is presented. This decomposition takes into account the morphology of the robot arm and the kinematic task definition as well. Two fields of applications are then investigated : - automatic generation of the end effector workspace, - predetermination of trajectories which avoid mechanical limits of the manipulator actuators. Finally an implementation of these methods and algorithms in the CATIA CAD system is given.

Nowadays, several general purpose CAD/CAM systems including robotics applications are commercially available. They require large computers facilities and sophisticated graphics workstations. Currently, trends is in dedicated systems which are implemented on micro or minicomputers and are devoted to specific applications. In this paper, such a dedicated interactive system is described with emphasis on the 3D data- base design specifications. Real-time and memory size constraints are keys requirements in the design. So far, this CAD/CAM software is intended for robot programming and CAD of workcells. A specific application involving synthetic vision generated by the system is also described.