Moving a wall on a blueprint is a pencil stroke. Moving it after drywall goes up runs $2,000 to $10,000, and five figures if it's load-bearing. This warehouse exists to catch the mistake while it's still a pencil stroke. The setup is almost insultingly simple. Projectors cast the floor plan onto a warehouse floor at exact 1:1 scale, straight from the architect's PDF. Clients walk the hallways, stand in the shower footprint, swing prop doors, and push cardboard furniture around the…