positional constraints over time as a space-time optimization problem in the tangent space of the curves driving the animation controls. Their method has the key properties that it allows for the manipulation of positions and orientations over time. https://www.lost-identification.com
Take a look at our collection of high-quality animated models of animals on Sketchfab: extinct marine creatures, realistic birds, bee, and goat, and cute stylized pets.
Extinct Marine Creatures
Here are two gorgeous marine creatures of the prehistoric times, Mosasaurus Hoffmannii and Dunkleosteus Terrell, that are made with Blender and Gimp by Kyan0s. The models go with smooth swimming animation.