I continue to explore tubular organic shapes with freely moving balls inside. This time I used a CAD program (Cheetah3D) to create a closed spline shape and then swept it with a circle. This way I created an organic shape with a constant diameter. I then opened this shape in ZBrush and used it as the basis for the design. Essentially this swept spline becomes the inside of the tube in the final design. Because it was created with a constant diameter circle, the balls will roll freely inside. See the descriptions for my other things for my design process or leave me a note and I will explain in more detail.

I've added a short video to the Downloads showing this thing being rotated and the balls rolling inside or it can be viewed here: https://vimeo.com/75143117

I used ReplicatorG to prepare the file, a MakerBot Replicator2 with the Replicator 2 slicing defaults and the following settings with white MakerBot PLA to do the printing:

Infill = 10%
Layer Height = 0.200
Shells = 1
Feedrate = 40
Travel Feed = 55
Temperature = 220

I used a raft with full support. It took over 19 hours to print with a length of 150 mm. Then it took several more hours to remove the support structure. Be patient and careful while doing this as the design is complex. Also it is tricky cleaning up the support structure from the balls once they are free to move.