This is a simple sewer set I was working on to learn modular asset creation in Blender. All of the base parts are included along with several prefabricated objects and a demo scene that shows you how they all snap together.

The project uses Blender asset manager to link the materials and objects. You need to set the file path to the unpacked folder for the project assets to properly display. Unpack the folder. In Blender go to edit->preferences->file paths and a path to the folder you unpacked.

The materials are made in Material Maker and I've included the project files if you want to edit them. The original materials are modifed works of Adamyuyu and are CC0 (public domain) licensed. All materials are PBR ready and include a color, rough, and normal map.

The assets work on a 4x4 grid and are intended to be in 1.0 to 0.5 increments. The floor, ceiling, and premade room peices can not be rotated otherwise you will see seams in the textures. I made directional peices for each asset labled N,S,E,W (north, south, east, west) or the direction the asset should face.