The Contour Hint point is used on the colour fill zone and brush lines; in other words, on Contour vectors. It allows you to control the line thickness and contour position. Also, if a contour is not animated correctly, you can use hints to correct the animation. For example, if a flag is not waving properly.
When adding a Contour Hint point, make sure to place it far enough away from the contour so you can see it snap to the contour.
Contour Hint points are yellow.
NOTE Do not place the Contour Hint directly on the line as it may look like it has snapped to the contour, when in fact, it has not and the morphing will remain unchanged.
NOTE To correct a brush stroke, place a hint on both sides of the line to indicate its thickness variations over time.