Controlling a component along a spline

Hi there, ive trying to make a component i use as “LineTrace_End” to move along a spline or somthing similiar with my gamepads joystick. Its a sidescroller so just want a quarter circle in front of the player char, so when i push the joypad “thowards” an angle the Linetrace will check if it is anything in that angle.

The problem is, I dont know how to limit the end line to a line, or to create said line, Il post a scetch of what i mean:

I want the LineTrace_End to follow the movement spline when i “point” with my joystick, if this was realy unclear, and i realy guess it is, since i having some seriuse issues wording the problem :frowning: