Remix of the left arm bones made available under CCBY license by user MySegmenter on the NIH3D Print Exchange (for some reason, the Model Origin box will not let me add the NIH link, so I added a link to my Sketchfab version there and the NIH link here in the text: [https://3d.nih.gov/entries/3DPX-016838](https://3d.nih.gov/entries/3DPX-016838)). I remeshed the bones to optimize them for 3D printing. The humerus, radius, and ulna can be printed separately or I have added the option for a connected radius and ulna which is easier for demonstrating their articulation with the humerus or for setting a particular bend before gluing. I have included the generic 3mf as well as exported the STL models in the recommended print orientation.

My changes to the original:

Since the original models were made for web display, they are very low poly. I remeshed each bone and applied smoothing to optimize them for 3D printing. For the combined radius/ulna, I added cylinders at the proximal and distal ends to connect them during printing. This feature makes it easier to articulate with the humerus if you want to set a specific bend to the arm before gluing or to demonstrate the articulation with the humerus.

Print settings:

• 0.20 mm layer height, 3 walls, 8% gyroid infill
• tree supports at 40 degrees (to make sure they don't fall!)
  • initial layer expansion = 5 mm
  • top z distance = 0.20 mm
  • top interface layers = 2
  • top interface spacing = 0
  • branch diameter = 2 mm

I added extra supports since these models are tall and skinny to make sure they don't fall over, but the supports come off very easily especially with matte PLA. I used Sunlu matte bone white. At the angles I have them set to, they fit fine on the Bambu A1.

Generic 3mf and STLs on Printables.