Friday, December 4, 2015

Tail and WTF Bone - Redux!

This is an update on two parts of the project: Re-creating the tail of a Thalattosaur and preparing a very strange bone.

The tail is mostly finished - all the centrums+neural arches are printed and fastened to a mounting base. The 65 tailbones add up to just about 6 feet long (180 cm to those of you in the logical world). I am still missing the chevrons that go underneath the centrums, but I haven't printed any of them yet. It was an interesting exercise in modeling, printing with both 0.5 and 0.3mm nozzles, temperatures, etc. I ended up printing the 45 largest bones with a 0.5mm nozzle and 0.2mm layer thickness. The smallest 20 had to be done with the 0.3mm diameter nozzle at 0.1mm layer thickness to maintain sufficient resolution. The largest bone took about 4 hours to print: the smallest about 7 minutes! I really like how the tail gets blunt out toward the end, like a crocodile, rather than very thin like an iguana.

As for the very strange bone, it is almost finished - and I STILL DON"T KNOW what it is!

It looks like a limb bone. It doesn't look like any of the other thalattosaur limb bones. The bone is very convoluted, with a very prominent ridge down the side and two very deep hollows. The ends of the bones - the articulating surfaces - are different as well. Whereas the Thalattosaur limb bone ends are concave with conical depressions for the cartilage, this bone has rounded ends with only a hint of hollowness. I really suspect that is a humerus of a very different type of animal. Perhaps it's from one of the ancient marine amphibians that were still alive then, or a crocodile or turtle ancestor! Maybe Pat and Eric at the University of Alaska Fairbanks can figure it out

This shows how deep the hollow in the side is. My fingertip is sitting in it - about 3/4 inch (1.8cm) deep!
Anyway, If I don't write again before the Holidays have a great time!
Sincerely, Greg Carr