I implemented a 2D triangulation fonction using Earcut. This isn’t the result I want because I want to triangulate 3D polygons (because rotations etc are computed somewhere else in the backend and I can’t access to a 2D polygon to triangulate it and then apply rotations with ThreeJS).

Thank you for your answers!
I’m a beginner with 3d development and ThreeJS I have no idea how I can do this. I know that in the backend rotations are made using a pivot point.
There is a big algorithm in the back for advanced calculations, and it provides me the polygon already positioned “so I just need to display it” but it’s quite hard.