Abstract The probabilistic roadmap approach is a commonly used motion planning technique. A crucial ingredient of the approach is a sampling algorithm that samples the configuration space of the moving object for free configurations. Over the past decade many sampling techniques have been proposed. It is difficult to compare the different techniques because they were tested on different types of scenes, using different underlying libraries, implemented by different people on different machines. We compared 12 of such sampling techniques within a single environment on the same scenes. The results were surprising in the sense that techniques often performed differently than claimed by the designers. The study also showed how difficult it is to evaluate the quality of the techniques. The results should help users in deciding which technique is suitable for their situation. Reference Roland Geraerts and Mark Overmars. Sampling Techniques for Probabilistic Roadmap Planners. In Conference on Intelligent Autonomous Systems (IAS-8), 2004, pp. 600-609. Full text: [pdf] Presentation: [ppt] A more elaborate version of this study can be found in Chapter 2 of my Ph.D. thesis. The successor of this study can be found here: reachability analysis.