This paper is devoted to geometric simulation of parabolic stream area in planar case. The stream is characterized by fuzziness of geometric parameters that is consequence of the technological parameters fuzziness. In this paper we consider the process of welding spark flying as a physical analogue of the parabolic stream. The method relies on consideration interval sets and combinatorial computing analyses of various geometric objects in planar case. In particular, this approach is used for parabola having interval numerical parameters. Various aspects of the parabolic stream such as shadow sub-areas and dangerous zones of the stream are discussed. We break up the area of the stream into interval closed sub-areas which correspond to interval physical parameters of metal drops. We also demonstrate that the most probable dangerous parts of welding protective suit can be discovered by developed model. The practical application of the method of geometric modeling of welding sparks makes it possible to determine the localized areas of the parts of a protective suit that need additional protection in terms of improving materials and design.