What is this kind of geometry called? I want to get Cartesian coordinates of the points of a curve (e.g. a bezier curve) based on the distance (e.g length of the arc) from the start point on the curve. To make this more clear, suppose I want to walk along a path with a constant speed, then I want to know my position for every time interval after I started. Could you provide me with keywords or links to search for this kind of geometry? Also please consult the following picture: 


What you want to do is parametrize the curve by arc length.
