Expert question - I want to find out the vector of the lowest vertex from the centre point of an object

Questions & Answers
1

Any Object. Mark it in the centre. Bee Line arrow down. Hit that final vertex. Get the vector point.

Then I want to raycast down from that vector.

So this would be the edge of an object, down from the centre to the bottom lowest y of the object.

Why am I do I need this. Ok colliders arnt working for me to achieve the physics I want. I need a centre point like this to detect things.

2

Here is some code to help you out:

using UnityEngine;

public class MyScript : MonoBehaviour 
{
	public MeshFilter meshFilter;

	private Vector3 lowestVertex;
	private Vector3 center;

	private void Start()
	{
		if(meshFilter == null || meshFilter.sharedMesh == null)
			return; // TODO: Error feedback.
		
		lowestVertex = FindLowestVertex();
		center = FindCenter();
	}

	private Vector3 FindLowestVertex()
	{
		float lowestYCoordinate = float.PositiveInfinity;
		var lowestVertex = meshFilter.transform.position; // Some sensible default.

		var vertices = meshFilter.sharedMesh.vertices;
		for (int i = 0; i < vertices.Length; i++) 
		{
			// Check for the lowest position in world space.
			Vector3 worldCoord = meshFilter.transform.TransformPoint(vertices*);*

  •  	if(worldCoord.y < lowestYCoordinate)*

  •  	{*

  •  		lowestYCoordinate = worldCoord.y;*

  •  		lowestVertex = meshFilter.transform.InverseTransformPoint(worldCoord);*

  •  	}*

  •  }*

  •  return lowestVertex; // In local space.*

  • }*

  • private Vector3 FindCenter()*

  • {*

  •  Vector3 center = meshFilter.transform.position;*

  •  Vector3 sum = Vector3.zero;*

  •  var vertices = meshFilter.sharedMesh.vertices;*

  •  for (int i = 0; i < vertices.Length; i++)* 

  •  {*

_ sum += vertices*;_
_ }_
_ center = sum / vertices.Length;_
_ return center;_
_ }*_

* private void FixedUpdate()*
* {*
* Vector3 centerWorld = meshFilter.transform.TransformPoint(center);*

* Debug.DrawLine(*
* centerWorld + new Vector3(0, -0.1f, 0),*
* centerWorld + new Vector3(0, +0.1f, 0),*
* Color.red);*

* Debug.DrawLine(*
* centerWorld + new Vector3(-0.1f, 0, 0),*
* centerWorld + new Vector3(+0.1f, 0, 0),*
* Color.red);*

* Vector3 origin = meshFilter.transform.TransformPoint(lowestVertex);*
* Debug.DrawRay(origin, Vector3.down, Color.green);*
* // TODO: Raycast*
* }*
}

“Any object” is a little too broad, so I assumed you were talking about meshes. If you don’t use the transform as a pivot, you can take the average of all vertices to find a center position.
To find the lowest vertex position in a mesh you have to loop through all the vertices and compare each one.