I designed this HO Scale Rooftop Billboard for my model railroad layout. I printed the parts with my Bambu Lab A1. There are 4 files:

1. Frame & Board - This is the bulk of the structure. It has slots in the back of the frame to slide the legs into.
2. Face - This fits over the front of the board, leaving a slot on the left side to slide signs in and out of the model.
3. Legs - Print 5 of these to slide into the corresponding slots on the rear of the frame.
4. Base - The legs slot into the base to form a stable base.

I used plastic cement (like Tamiya Extra Thin or Plastruct Bondene) to re-enforce the joints.

The billboard fits a sign measuring 6.5" x 2". I used a Cricut Maker to cut the sign. I finsih the billboard with platforms and ladders from Tichy Train Group (#8001 Open Grate Platform & #8002 Safety Cage Ladder).