Get / Calculate edges of a 3D object - C #

[gabrieltva]

I need to get all vertices in the edge position of a determinate object 3D (in this case a path).

See the image:

My question is, how can I get only the edges vertices, like the image?

[Xarbrough]

You can use a [convex-hull-algorithm][1] to find the outer edge of a point set. There are a few to pick from, but here’s an example of Jarvis march:

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

public class FindConvexHull : MonoBehaviour 
{
	public List<Vector2> points;
	public float gizmoSize = 0.1f;

	private void OnDrawGizmos()
	{
		Gizmos.color = Color.white;
		foreach(var point in points)
			Gizmos.DrawSphere(point, gizmoSize);


		var hull = ConvexHull(points);
		if(hull != null)
		{
			Gizmos.color = Color.green;
			for (int i = 0; i < hull.Count - 1; i++) 
			{
				Gizmos.DrawLine(hull*, hull[i+1]);*

•  	}*
  

•  	Gizmos.DrawLine(hull[0], hull[hull.Count - 1]);*
  

•  }*
  

• }*

• private List ConvexHull(List points)*

• {*

•  List<Vector2> hull = new List<Vector2>();*
  

•  if(points.Count < 3)*
  

•  	return hull;*
  

•  int leftMost = 0;*
  

•  for (int i = 0; i < points.Count; i++)* 
  

•  {*
  

_ if(points*.x < points[leftMost].x)_
_ leftMost = i;_
_ }*_

* int pointA = leftMost;*
* int pointB;*
* do*
* {*
* hull.Add(points[pointA]);*
* pointB = (pointA + 1) % points.Count;*

* for (int i = 0; i < points.Count; i++)*
* {*
_ if(GetTurn(points[pointA], points*, points[pointB]) == 2)
pointB = i;
}*_

* pointA = pointB;*
* }*
* while (pointA != leftMost);*

* return hull;*
* }*

* private float GetTurn(Vector2 a, Vector2 b, Vector2 c)*
* {*
_ var val = (b.y - a.y) * (c.x - b.x) - (b.x - a.x) * (c.y - b.y);_

* if (val == 0)*
* return 0;*

* if (val > 0)*
* return 1;*

* else*
* return 2;*
* }*
}

[1]: Gift wrapping algorithm - Wikipedia