I am searching a way to create a 2D/3D spline linear interpolation function which takes a spline segment and a double amount value (in [0;1] range) as input and return a double[] (x;y;z) point as output.

The result is the (x;y;z) point along the curve at (amount * curve length) distance of the starting point.

I never worked with splines and don't know about their structure.

Any documentation resources will be welcome, or advice to achieve this.