The Reach ODSTs share a lot of the same base as the Reach Army Troopers and Marines. In particular they seem to share the same base shin and boot topper as the Reach Marine, with an additional knee plate. A lot of the ODSTs seem to have a small topper seen some of the Marine shins, but with a larger more ovoid Knee plate that looks similar to many common modern day knee plates.
Reach Marine Shin PDO (which does not have the topper):
This is a comprehensive zip file including numerous files from multiple artists. Contents of zip-file: halo-reach-unsc-marine-chest.pdo Modeler: Satchmo III halo-reach-unsc-marine-helmet.pdo Modeler: Lee halo-reach-unsc-marine-shin.pdo Modeler...
www.405th.com
Moe also has STLS of the Reach Marine Shin here that do have the topper:
Download files and build them with your 3D printer, laser cutter, or CNC.
www.thingiverse.com
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