3d Joiner Clips
These are the white clips in the picture on top of the walls....
Designed to put on top of a 3d layout to hold walls in alignment with each other, assumes wall thickness of no more than 0.8mm (2x 220gsm card fits).
Contains Straight, Corner, T and X junctions.
Adjust height via scalling as required, I found a 4-5mm height worked.
Successfully printed, fdm with .2 layer.