This panel is essentially a diagonally split square Polypanel. It has two standard edges connected at a right angle, and a single longer edge (that hypotenuse homie!)
What are Polypanels?
"Welcome to the world of Polypanels, a system of snap together parts that let you build whatever you want! It’s like an open-ended construction toy for making functional things, harnessing the power of 3D printing and the community to make it truly limitless."
Printing Guidelines
A high wall thickness of 5 shells/perimiters will ensure solid snap connectors. From there settings can vary based on your desired outcome. Print solid for the most robust and long lasting joints, or print a lower infill with 0 top and bottom layer thickness for a cool exposed infill pattern.
This download contains many variations, including two part versions for printing with dual extruders or multiple processes. Combine the _"Edge.stl" and one of the _"Inner.stl" files.