auditorium interior 3d model

Create a small auditorium interior structure without seats for a public speaking simulator. The environment should include a stepped seating platform where chairs can be placed later. The floor should have three stepped levels like a theater layout, with the front level lowest and the back levels higher. Add a central staircase aisle between the seating platforms similar to real auditoriums. Include left and right side walls, a back wall, and a full ceiling roof above the room. The ceiling should have simple recessed or panel lights. The stepped floor should look like a solid platform so chairs can be placed on top. The environment should feel like a small conference auditorium room. No chairs or people included. Game-ready 3D environment, realistic materials, clean geometry, no grayboxing.