OpenCascade Primitives BRep - Box eryar@163.com Abstract. BRep is short for Boundary Representation. Boundary Representation gives a complete description of an object by associating topological and geometric information for solid modeling. In this case, objects are described by their boundaries. There are two types of information in BRep: Topological information and Geometric information. This paper is concerned with the Box BRep in OpenCascade, and also show how to use Tcl script to dump box BRep info. Key words. OpenCascade, BRep, Boundary Representation, Box, Winged-Edge Structure 1.