Hey, thanks for the feedback 😊. I do agree that the UX could have been better. I was contemplating using the camera angle when figuring out the axis of rotation. I decided to just use the axis on which you click, since I thought depending on the camera view might not be intuitive.
I saw the disappearing issue too, but only once, so I couldn't figure it out why it was happening. I'm just guessing that the corners I cut to render the pieces was too much for Godot to handle.