13. Model Reference

13.1. Pose

Model pose can be exported to .c3d and .fbx files.

The .c3d files contain the 4x4 pose matrices for each model segment and the local coordinates of the anatomical landmarks of the distal segments of the model (feet, hands, head). These files can be processed using Visual3D.

The .fbx files contain the hierachical skeleton, pose, and bone meshes of the animation model. The first frame of the file contains the model in a “T-Pose”.

13.2. Model Description

_images/model.png

The Standard Theia3D kinematic model.

The standard kinematic model consists of two kinematic chains - one for the upper body and one for the lower body - and a six degree of freedom head. The kinematic chains are hierarchical collections of segments connected by joints as described below. There are options to use free (6dof) joints for the shoulder and ankles. There is also an animation specific model that has a single kinematic chain comprising the lower body, upper body, and head, with the pelvis as the root segment.

Head

  • Parent: Lab

    • Origin: Midpoint of ears

    • Joint: Free joint (6 DOF)

Upper Body

  • Torso

    • Parent: Lab

    • Origin: Base of neck

    • Joint: Free joint (6 DOF)

  • Right Clavicle

    • Note: for Animation Model, i.e. only included in FBX file outputs

    • Parent: Torso

    • Origin: Base of neck

    • Joint: Two rotational degrees of freedom (about anterior-posterior and superior-inferior axes)

    • Proximal: Base of neck

    • Distal: Right shoulder

  • Right Upper Arm

    • Parent: Torso

    • Origin: Right shoulder

    • Joint: Three rotational degrees of freedom or a free joint (6 DOF)

    • Proximal: Right shoulder

    • Distal: Right elbow

  • Right Lower Arm

    • Parent: Right Upper Arm

    • Origin: Right elbow

    • Joint: Two rotational degrees of freedom (flexion/extension, pronation/supination)

    • Proximal: Right elbow

    • Distal: Right wrist

  • Right Hand

    • Parent: Right Lower Arm

    • Origin: Right wrist

    • Joint: Two rotational degrees of freedom (flexion/extension, ad/abduction)

    • Proximal: Right wrist

    • Distal: Right mid hand

  • Left Clavicle

    • Note: for Animation Model, i.e. only included in FBX file outputs

    • Parent: Torso

    • Origin: Base of neck

    • Joint: Two rotational degrees of freedom (about anterior-posterior and superior-inferior axes)

    • Proximal: Base of neck

    • Distal: Left shoulder

  • Left Upper Arm

    • Parent: Torso

    • Origin: Left shoulder

    • Joint: Three rotational degrees of freedom or a free joint (6 DOF)

    • Proximal: Left shoulder

    • Distal: Left elbow

  • Left Lower Arm

    • Parent: Left Upper Arm

    • Origin: Left elbow

    • Joint: Two rotational degrees of freedom (flexion/extension, pronation/supination)

    • Proximal: Left elbow

    • Distal: Left wrist

  • Left Hand

    • Parent: Left Lower Arm

    • Origin: Left wrist

    • Joint: Two rotational degrees of freedom (flexion/extension, ad/abduction)

    • Proximal: Left wrist

    • Distal: Left mid hand

Lower Body

  • Pelvis

    • Parent: Lab

    • Origin: Midpoint of hips

    • Joint: Free joint (6 dof)

  • Right Thigh

    • Parent: Pelvis

    • Origin: Right hip

    • Joint: Three rotational degrees of freedom

    • Proximal: Right hip

    • Distal: Right knee

  • Right Shank

    • Parent: Right thigh

    • Origin: Right knee

    • Joint:Two rotational degrees of freedom (flexion/extension, ad/abduction) or three rotational degrees of freedom (flexion/extension, ad/abduction, internal/external rotation)

    • Proximal: Right knee

    • Distal: Right ankle

  • Right Foot

    • Parent: Right Shank

    • Origin: Right ankle

    • Joint: Three rotational degrees of freedom or a free joint (6 DOF)

    • Proximal: Right ankle

    • Distal: Right mid foot

  • Right Toes

    • Parent: Right Foot

    • Origin: Right mid foot

    • Joint: One rotational degree of freedom (flexion/extension)

    • Proximal: Right mid foot

    • Distal: Right big toe

  • Left Thigh

    • Parent: Left

    • Origin: Left hip

    • Joint: Three rotational degrees of freedom

    • Proximal: Left hip

    • Distal: Left knee

  • Left Shank

    • Parent: Left thigh

    • Origin: Left knee

    • Joint: Two rotational degrees of freedom (flexion/extension, ad/abduction) or three rotational degrees of freedom (flexion/extension, ad/abduction, internal/external rotation)

    • Proximal: Left knee

    • Distal: Left ankle

  • Left Foot

    • Parent: Left Shank

    • Origin: Left ankle

    • Joint: Three rotational degrees of freedom or a free joint (6 DOF)

    • Proximal: Left ankle

    • Distal: Left mid foot

  • Left Toes

    • Parent: Left Foot

    • Origin: Left mid foot

    • Joint: One rotational degree of freedom (flexion/extension)

    • Proximal: Left mid foot

    • Distal: Left big toe