in 3D, how can I cut away pieces of an octagon, while keeping a seamless texture?

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:bust_in_silhouette: Asked By warfpea

Update: I found a material flag called “World Triplanar,” which seems to work as if the texture was projected from above my shape, but it doesn’t move or rotate with the shape like I need D:

In my game I have a 3D scene, with a circle of 8 triangles making up a flat octagon. I want to draw a repeated texture seamlessly on top of this octagon, while still being able to enable and disable triangles individually.

here you can see each piece has the same independent texture, instead of a single image
this should be a single flat texture. even more obvious when I animate the offset

I also need to be able to offset the texture whenever, and make sure it still looks right.

here you can see the effect I’m going for, except this is a single mesh and I can’t disable pieces of it
correct sorta

In Gamemaker using 2D I would use a full octagon and mask out the disabled triangles, but I’m new to Godot and 3D in general so I’m not sure where to start with this. Any ideas? should I be using multiple nodes for the separate triangles at all?