Center of Mass Estimator

Developed by **Professor Fedel** (Biomechanics & Kinetics)

Load an image from your drive, or simply **paste** a screenshot (Ctrl+V / Cmd+V) here!

Click on the **Input Image** while holding **SHIFT** to set the **Axis of Rotation**.

0 px

Input Image (Draw Lasso Here)

Processed Output (COM Marked)

Center of Mass: (X: ?, Y: ?)

User Instructions

  1. **Load Image:** Click "Choose File" or paste a screenshot (**Ctrl+V** / **Cmd+V**) of the object you wish to analyze.
  2. **Draw Lasso:** On the **Input Image (left)**, click and drag your mouse to draw a closed loop (**lasso**) around the entire area of interest.
  3. **Set Axis (Optional):** Hold **SHIFT** and click on the **Input Image** to set the **Axis of Rotation**.
  4. **Refine Boundary (Optional):** Use the **Boundary Offset** slider to move the lasso boundary **inwards** (negative volume).
  5. **Calculate COM:** Click either "Calculate Center of Mass (Original Lasso)" or "Apply Offset & Recalculate".
  6. **Analyze Results:** The **Input Image** shows the COM with its vertical projection and, if the Axis is set, a **yellow Moment Arm** (horizontal line) indicating the perpendicular distance from the COM to the axis height.
**NOTE ON COM VALIDITY:** The Center of Mass calculation relies on a fundamental assumption of **symmetry** (e.g., feet side-by-side in sagittal view, similar constraints in frontal plane). For the result to be biomechanically accurate, the view of the object must represent a plane of symmetry.