Node Attachment

So working through the node attachment. I started to think about how the joint could be flexible. So starting from a equal spacing on the triangle of 120 degrees between each attachement point. I wanted the attachement to rotate about a point so I thought that a circle with a track for something to ride in. Then I needed the attachement points to pivot in the Z direction so I figured that a sphere could pivot in the track and thus give it movement. Then another track sits on the top to anchor the 3 pivot points in the track and then that get clamped down with the a small disc and a bolt.