https://youtu.be/3UYPDJvNihA https://youtu.be/mDyeoVmsN-0 "Marblevator, Caterpillars" is my latest Marblevator design. The model was 3D printed using three material types: PLA, PVA and TPU. The "caterpillars" in this model are four section ball bearing carriers containing four 8mm ball bearings. The carrier is 3D printed in PLA on a PVA raft using PVA supports. PVA is a water soluble material so when 3D printing is completed, I simply drop the caterpillar in warm water and allow time for the PVA raft and supports to dissolve. The belt in this model is 3D printed in TPU on a TPU raft. There are eight pockets on the belt designed to hold eight 6 by 1.5mm neodymium magnets. The magnets are spaced such that the belt will pick up the caterpillars from the end of the track and transport them upward to the start of the track. Small paddles at the end of each magnet group assist in transferring the caterpillar to the track. The remaining components of the model were 3D printed in PLA. It's not the most reliable Marvblevator I've designed, but it does intrigue the grandkids so I like it! As usual I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to comment as I do make plenty of mistakes. Designed using Autodesk Fusion 360, sliced using Ultimaker Cura 4.12.1, and 3D printed in PLA on Ultimaker S5s and an Ultimaker 3 Extended.