A 3d printed shingle that snaps together and can be glued/nailed down for small buildings. It can be made from whatever material you have to print with, I'd use TPU for it's UV protection and flexibility, ASA, ABS, etc, PLA will also work for it's biodegradability. You can spray a hydrophobic coating on it to make rain and snow fall right off. Ideal for dog houses, sheds, kids toy houses, etc in this size and with the right material/modifications can be made to look like boards, I went with the slick design for weather and functional use.

I haven't made a full sized one for regular houses yet but I'd use an injection molder or resin mold for those. If you have or can use a regular resin molds the hydrophobic additive for resins is from NBD nano.
https://www.nbdnano.com/solutions/additives/repellshell/
Not sure if the stuff works with injection molds based off how it works when it cures.

3d printer is still broken so I haven't been able to make anything yet and my computer got fried, but hopefully it will be fixed soon.

Supplies

3d printer

stl file

filament of choice

Step 1: Print File

Download file and have as many shingles as required for the job printed the shingles are 300mmx300mm.

Step 2: Nail And/or Glue Down From the Top Down and Snap the Panels in Place

Start from the top middle of the roof and alternate rows by half a shingle wide each row nailing, screwing and/or gluing them down until you reach the bottom of the roof. It changes from the typical shingling pattern due to the snap fixtures on the shingles.

Step 3: Add Crown, Pitch and Angle Will Vary

The pitch and angle will vary depending on roof so what I would do is take a simple measurement, jump on tinkercad and use the shingle as a hollow shape and match the right length on a 5mm thick, or however thick you want the material crown.

Whether you make it out of PLA, ABS or TPU will determine if the shape can be flat for TPU because it flexes or if you need to make an angled crown with rigid material.

Have fun shingling.