MakeStructuralGrid.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// @kurtdekker - making a structural grid in Unity3D
// to use: drop this in a blank scene and watch!
//
// NOTE: this makes a web with a central link.
// you could do other connectivity strategies obviously.

public class MakeStructuralGrid : MonoBehaviour
{
	void Start ()
	{
		// make a floor to bang down on
		GameObject floor = GameObject.CreatePrimitive( PrimitiveType.Cube);
		DestroyImmediate( floor.GetComponent<Collider>());
		floor.transform.position = new Vector3( 0, -4.5f, 0);
		// tilt the floor a bit
		floor.transform.rotation = Quaternion.Euler( 0, 0, Random.Range( -5.0f, 5.0f));
		floor.transform.localScale = new Vector3( 16, 1, 1);
		floor.AddComponent<BoxCollider2D>();

		// chose a random angle for the dropped chunk
		float angle = Random.Range( 0.0f, 360.0f);
		Quaternion rotation = Quaternion.Euler( 0, 0, angle);

		int across = 5;
		int down = 3;

		int centerx = across / 2;
		int centery = down / 2;

		Rigidbody2D[,] bodyGrid = new Rigidbody2D[across,down];

		// make and record all bodies
		for (int j = 0; j < down; j++)
		{
			for (int i = 0; i < across; i++)
			{
				int x = i - across / 2;
				int y = j - down / 2;
				Vector3 position = new Vector3( x, y);
				position = rotation * position;
				position += Vector3.up * 4.0f;

				GameObject chunk =GameObject.CreatePrimitive( PrimitiveType.Sphere);
				DestroyImmediate( chunk.GetComponent<Collider>());
				chunk.transform.position = position;

				chunk.AddComponent<CircleCollider2D>();
				Rigidbody2D rb2d = chunk.AddComponent<Rigidbody2D>();
				bodyGrid[i,j] = rb2d;
			}
		}

		Rigidbody2D centerBody = bodyGrid[centerx, centery];

		// connect them to the center one!
		for (int j = 0; j < down; j++)
		{
			for (int i = 0; i < across; i++)
			{
				Rigidbody2D body = bodyGrid[i,j];
				if (i == centerx && j == centery)
				{
					// noop
				}
				else
				{
					FixedJoint2D fj = body.gameObject.AddComponent<FixedJoint2D>();
					fj.connectedBody = centerBody;
					fj.breakForce = 300;
				}
			}
		}
	}
}