Knee Animation

This project was done during an internship with Amerra. The goal of this project was to show the proper anatomical movement of a bending knee and what happens when the ACL is torn.

Components responsible for:

Rigging
Animation

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Part 1: Setting up the joints

For this project I had to forego the standard IK knee set up in order to properly incorporate the patella movement. My solution was separate fibula and tibia from the femur in the rig. This separation allowed for independent movement of these two parts which was needed to incorporate the ACL tear simulation.

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Part 2: Skinning the Bones

Another advantage of keeping the fibula and tibia separate from the femur was for binding the geometry to the joints. This being an anatomical representation of a human knee, painting skin weights was very straight forward, because human bones do not bend the skin weight of each mesh are only influenced by one joint.

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Part 3: The Muscles

One of the most challenging parts of this project was achieving proper muscle deformations. I first tried using Maya Muscles, but when they would not deform the geometry, so I turned toward blendshapes.

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Part 4: The ACL Tear

Working on the ACL tear simulation was challenging, because there needed to be a way of taking a single mesh that tears into two meshes. To solve this problem, I created a second 'torn' mesh for the ACL simulation.

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