About this 3D model

Recently I wanted to make a small vertically sliding pet door using 3mm perspex/acrylic and needed something to hold and guide the perspex through its vertical range. This simple modular track is what I came up with. It is easy to print, slots together to allow longer runs, and has 4 mounting holes. The insets haven't been made too snug so some degree of care is needed in aligning pieces for longer runs to ensure smooth tracking.