From Skin to Skeleton: An Interactive Viewer

Overview

This interactive simulation demonstrates the core concepts from the research paper "From Skin to Skeleton: Towards Biomechanically Accurate 3D Digital Humans". The goal of the research is to bridge the gap between computer graphics models, which are good at representing the body's surface, and biomechanics models, which are necessary for anatomically correct movement analysis.

• SMPL (Skinned Multi-Person Linear Model): A popular model in computer graphics that accurately captures the human body's shape and skin surface. However, its underlying "skeleton" is a simplified kinematic tree not based on real anatomy, which can lead to unrealistic joint movements. In this viewer, SMPL is shown in pink.
• SKEL Model: The new model introduced in the paper. It augments the SMPL model with a biomechanically accurate skeleton. This means the joints are in the correct anatomical locations, and movements like forearm rotation (supination/pronation) are modeled correctly. The SKEL model here is shown with an orange skin and white bones.

By comparing these two models, you can see how the SKEL model provides a much more realistic internal structure for the same surface movements.

How to Use

• Rotate View: Click and drag (or touch and drag) on the canvas to rotate the models. You can also use the Arrow Keys.
• Zoom: Use your mouse scroll wheel (or pinch-to-zoom on a touch device) to zoom in and out. The `+` and `-` keys also work.
• Pan View: Hold down the `Shift` key while dragging to pan the view.
• Select Animation: Use the dropdown menu to choose between different motion sequences.
• Scrub Animation: Drag the "Frame" slider to manually move through the animation timeline.
• Play/Pause: Toggle the animation playback.
• Toggle Visibility: Use the switches to show or hide the SMPL skin, the SKEL skin, and the SKEL skeleton to compare them easily.
• Play Demo: Click this button to see an automated tour of the viewer's capabilities, cycling through animations and visibility settings.
• Sonification: The "Sound" button enables or disables audio feedback, where joint movements generate subtle tones based on their speed. It is off by default.

Future Directions

The development of biomechanically accurate models like SKEL opens up many exciting possibilities:

• Medical Applications: Creating personalized digital twins for surgical planning, rehabilitation tracking, and ergonomic analysis.
• Sports Science: Analyzing athletic performance with greater accuracy to optimize technique and prevent injuries.
• Realistic Animation: Generating more lifelike character animations for films and games by grounding them in real human anatomy and physics.
• Virtual Reality: Driving VR avatars with more natural and believable movements, enhancing the sense of presence and immersion.

This work is a significant step towards creating true "digital humans" that not only look real on the surface but also move and function like real people from the inside out.