Is there any way to edit a Shape3D variable(say, a BoxShape3D) from the 3D editor the same way you would edit it in a native Node like a CollisionShape3D?
This is what I currently have, I mistakenly expected for the shape to become visible in the 3D editor as soon as the variable was assigned. This wasn’t the case.
I don’t think it’s possible unfortunately, because the Shape3D itself has no transform (meaning no position, rotation and scale), which is required to be properly shown in the editor. That’s why you need to place it within the CollisionShape3D node, which has a transform and can be shown and edited in the editor - notice that playing around with the shape in the editor, you are changing both Shape3D size values and CollisionShape3D transform values at the same time.
As a workaround you could edit the Shape3D from within the CollisionShape3D node, and then copy over the shape to its final destination.