I'm new to shaders so it'll just require some experimentation. After some looking on the GMS forums I found this tutorial, if anyone is interested: https://forum.gamemaker.io/index.php?threads/toon-and-outline-shaders.73138/
And hey Gizmo, thanks a lot for making these tools dude. Super intuitive and helping me learn 3D immensely. I'm gonna take a crack at your 3seqsD joint next