Unity Spline Basics (Move a GameObject. along the length of a spline)

FollowSpline.cs

// Gist attached to YouTube video, please do not delete. See my YT channel, link in bio.

using UnityEngine;
using UnityEngine.Splines;
using Unity.Mathematics;

// This is applied to a boxing target flying at the user in my example.

// The whole Spline functionality comes from Unity's Window->Package Manager, and is in the Unity
// Registry.

public class FollowSpline : MonoBehaviour

{
    public SplineContainer spline;
    private float speed = .3f;
    private float t = 0f;

    // Update is called once per frame
    private void OnValidate()
    {
        if (spline == null)
        {
            Debug.LogError($"{name}: Spline reference is missing!", this);
        }
    }
    
    void Update()
    {
        // Here I'm just preventing a pileup of targets that have 
        // flown past the user.
        if (t >= 1)
        {
           Destroy(gameObject);
           return;
        }
        
        // Evaluate(...) here is expecting a value from 0..1, to interpolate the position
        // along the spline's length. (also try the prompt: Tell me about 'out' parameters in C#...)
        t += speed * Time.deltaTime;
        spline.Evaluate(0, t, out float3 pos, out _, out _);

        // ... and then just write that interpolated position to this GameObject.
        transform.position = pos;
    }
}