[ame="http://www.youtube.com/watch?v=UPuGZu-Eic8"]YouTube - TF2 - Sawmill Rain Particle Modification[/ame] If you have been using the Sawmill or Viaduct weather effects, you may have noitced that the particles simply falls through all objects so I've modified the system so the particles no longer pass through solid objects! :thumbup1: This modified particle system works almost exactly like the ones found in Sawmill and Viaduct. For Sawmill there are 2 rain effects; env_rain_001_collision (1024 units) and env_rain_002_collision (256 units). If you have already being using the Sawmill particles then simply append '_collision' to the end of the name that each of your info_particle_systems point to. For Viaduct simply append '_collision' or '_collision_cheap'. The difference between Viaduct's '_collision' and '_collision_cheap' is that the first allows particles to stay on the surface for a short period of time which is quite expensive whilst the latter kill the particles as soon as it hits a solid surface. Use them wisely. Update: Added collision to Viaducts snow! Note - 16th September Valve have added an option to disable weather effects but unfortunately particles that are flagged as weather are hardcoded. You can read Robin's response here. How To Install and Pakrat Place the particles_manifest.txt in your tf/maps folder Rename it to yourmap_particles.txt Pakrat the .pcf from your particles folder and the .txt Edit the location of each item so it reads as 'particles' for the .pcf and 'maps' for the .txt You will get console errors for each set of particles along the lines of "unable to precache particle...". Ignore this. I hope some of you will find this useful.