The option angle from curve works similar to closest point option. The difference is that an additional fix tilt angle can be given to tilt the tool axis centerline from the tilt curve to the direction of spindle main direction. This angle is the parameter fixed tilt angle. A value of 0 degrees here would make this option behave like closest point option.
The other differences that the direction of your tool axis is the projected length between your present toolpath point and the tilt curve. So it is the 2D distance.
The following example shows a surface with a tilt curve beneath. You can see that the tool axis has the same direction like projected distance between surface and present toolpath point.
Fixed tilt angle
