Hi,
Sample curve needs to be used with the x axis as time and the y axis as the value over time.
so for your jump, make a curve that represents the jump over 1 second for example, and then as your player jumps, maintain a timer of the jump, and sample the curve until you reach 1 second, the curve will tell you the height of the player.
make your sample curve y value normalized as well ( 1 being the max jump height).
so now you have a sample curve spanning over 1 seconds in duration and 1 unit in height. you can then apply some multiplers for the duration ( say you want your jump to last 3 seconds, you divide your sample time by 3 to get the current height), and ou can also define the maximum height ( say 5 units in height, multiply the current sample value for a given time by 5).
this way you have a very powerful curve sampling strategy.
Bye,
Jean