Visualization of Catmull-Rom Spline Generation
When learning about Catmull-Rom splines, I was looking for visualizations to get an an intuition behind how they get constructed. While there are many explanations and demos around the internet, I couldn't find any that graphically shows the role and behavior of the various intermediate/helper points at work.
The following is a plotting of the build-up based on the Wikipedia page's definition. C follows the final line, and is derived linearly from B points, which in turn are derived linearly from A points, and those from the control points P.
You can move around the four blue control points to change the curve. Manually move the black slider to jump to any point along the parametrization between t1 and t2. Change the alpha slider to switch between different flavors (α=0.5 is cetripetal Catmull-Rom). Moving or zooming the viewport clears traces.