UnityScript dynamically created mesh, object reference error

Unity Engine
1

Hi, new to Unity and scripting in general. I’ve been playing around with dynamically created meshes and am hitting a couple of problems.

Here is my code:

#pragma strict
@MenuItem("Custom/New Wall...")

static function addNewWall() {

	var newVerts : Vector3[];
	var uv : Vector2[];
	var tris : int[] = [0,1,2,2,1,3];
	
	var newWall : GameObject =  new GameObject();
	var newWallMesh : Mesh = new Mesh();
	
	newVerts[0] = Vector3(2,0,0);
	newVerts[1] = Vector3(0,3,0);
	newVerts[2] = Vector3(-2,0,0);
	newVerts[3] = Vector3(0,-3,0);
	
	uv[0] = Vector2(0,1);
	uv[1] = Vector2(1,1);
	uv[2] = Vector2(0,0);
	uv[3] = Vector2(0,1);
	
	newWallMesh.vertices = newVerts;
	newWallMesh.uv = uv;
	newWallMesh.triangles = tris;
	
	newWallMesh.RecalculateNormals ();
	
	newWall.AddComponent(MeshFilter).mesh = newWallMesh;
	newWall.AddComponent(MeshRenderer);
	
	AssetDatabase.CreateAsset (newWallMesh, "Assets/NewWall.asset");
}

I’m being given a “NullReferenceException: Object reference not set to instance of object” error at line 14.
Is it saying that I’m trying to refer to newVerts[0] as if it’s a copy of an object called newVerts?
or is it something to do with my newVerts variable not being given a definite quantity of Vector3’s to contain?

The unity mesh documentation may need expanding to include adding some vertices to a newly created mesh.

The section about building from scratch assigns no actual vertices to the mesh.

Thanks in advance?

2

You need to create an array of the correct size before you start assigning values to it.

The documentation for Mesh is pretty sparse, but there is a more detailed example here: http://docs.unity3d.com/Documentation/Manual/Example-CreatingaBillboardPlane.html