The below post is related to an archived discussion
[start here] I am using 5.5 version and have the same problem. The walls are defined in the wall catagory and I have tried, without changing anything else, the following wall conditions bounce, diffuse scattering and isotropic scattering, Mixed diffuse and specular reflection (probability 0.5) general reflection (x=3m.s, y=-5m/s reflected velocity). The software seems to be ignoring the walls?