This pack includes modular air ducts ( round and square ) and also tile set with separate tiles, which allows you to create custom duct segments. Duct tile set can be snapped by 50cm grid, other meshes by 10cm. This pack also includes customizable layered materials and example map with assets assembled together for reference.

You can find full list of meshes in the screenshot gallery.

To change layered material parameters and layers you need to activate experimental option in Project Settings/Rendering ( under Engine group )/Support Material Layers ( under Materials group) and restart your project.