Abstract: A process is provided for preparing a three dimensional object such as a mandrel for forming envelopes for mammary prostheses or other implantable medical device by dipping the mandrel, etc. The envelopes are provided with micropillars on the exterior surface which resembles the mandrel surface in negative relief. According to the process a workpiece of solid stock material such as polymer is provided in the shape of the desired prostheses. It is positioned for rotation on a supporting shaft or other holding mechanism. A pulsing laser beam, directed at the workpiece is moved in a plane parallel to the axis of rotation of the workpiece while the beam is maintained approximately perpendicular to the workpiece surface. The rate of pulsing of the laser beam and the speed of rotation of the workpiece are controlled to produce patterns of blind micro-holes onthe surface of the workpiece.