Aligning two child objects to get spawn location

Questions & Answers
1

Hi folks. I am making a train game and I am trying to figure out the track. I wonder if someone could help me with an approach.

Right now, using a Vector3 offset, I can make 1 kind of track work (hooking up straight pieces to straight pieces for example) But the problem comes in when I mix in different sized pieces. I am trying to avoid a nasty if else chain where I say, if the previous track piece was a straight piece here is your offset, if it was a curve piece here is your offset etc.

What I would dearly love to do is make two child objects, a lock and a key on each track piece, and say to the next piece, move to the position where your lock child is aligned with the previous pieces key child.

Here is a picture that may explain this better.

197541-lockkey.png
197541-lockkey.png760×418 191 KB

Can some Unity hero point me to the right approach for this? How would I align the child of one object with the child of another?

Many thanks in advance

2

Something like this would help? You can get Left and Right of Straight and Curved.

using System.Collections;
using System;

class Vector3 { 
    
    public float x = 0;
    public float y = 0;
    public float z = 0;
    
    public Vector3(float xx, float yy, float zz) { x=xx; y=yy; z=zz;}
}

interface Piece {
    public Vector3 Left();
    public Vector3 Right();
}

class Curved : Piece {
    Vector3 _left = new Vector3(3, 2, 1);
    Vector3 _right = new Vector3(6, 5, 4);
    public Vector3 Left() { return _left; } 
    public Vector3 Right() { return _right; }
}

class Straight: Piece {
    Vector3 _left = new Vector3(1, 2, 3);
    Vector3 _right = new Vector3(4, 5, 6);
    
    public Vector3 Left() { return _left; } 
    public Vector3 Right() { return _right; }
}
public class HelloWorld
{
    public static void Main(string[] args)
    {
        ArrayList items = new ArrayList(10);
        for (int i = 0; i < 10; i ++)
        {
            if ( i % 2 == 0 ) 
            {
                items.Add(new Straight());
            }
            else 
            {
                items.Add(new Curved());
            }
        }
        
        foreach(Piece item in items)
        {
            Console.WriteLine (item.Left().x);
        }
    }
}
3

@yoonix2 Thanks so much for your generous answer.

I wasn’t expecting an actual code example, just an approach, so I really appreciate it.