PADrend stands for Platform for Algorithm Development and Rendering – a software system for virtual walkthroughs in complex three-dimensional scenes. PADrend is developed since 2007 in the research group Algorithms and Complexity at the Heinz Nixdorf Institute, University of Paderborn. The main developers are Benjamin Eikel, Claudius Jähn, and Ralf Petring. The goals of PADrend are the harmonization of development efforts, the establishment of a basis to compare 3D rendering algorithms, and the provision of an adequate basis for research and teaching. Among other things, PADrend is utilized to develop and evaluate new rendering algorithms, to support students in writing their bachelor's and master's theses, and to do design reviews of complex virtual scenes on the HD visualization center. PADrend is based on a collection of C++ libraries. These libraries define bindings to the EScript scripting language. PADrend consists of a set of plug-ins, which are written in EScript and use the functionality of the base libraries.