Mesh vertices appear in a wrong position

Unity Engine
1

Hi all,

I hope someone has a solution to this strange issue. I am trying to get the coordinates of a mesh plane which is rotated in space and scaled a little. What I get is the coordinates of this plane BEFORE it was rotated or scaled (original position of the plane).

The attached images shows:

  1. the rotated plane on the right - I want to get the vertices from this plane
  2. a collection of capsules which I generated to visualize the vertices I get - these appear in the original place and size of the plane. It seems like the transformations made to the plane were ignored.

The plane is a primitive in Unity. I tried to import a different kind of mesh as FBX, but got the same result.

The code I’m using is below. Any idea why this happens?

void GetWorldVertices()
{
// Get the mesh from the gameobject
currentMesh = currentMeshObject.transform.GetComponent().sharedMesh;

// get the vertices in local coordinates
localVertices = currentMesh.vertices;

// transform them into the world coord system
for (int i = 0; i < localVertices.Length; i++)
{
Vector3 localV = localVertices*;*
Vector3 worldV = transform.TransformPoint(localV);
worldVertices.Add(transform.TransformPoint(worldV));
}

// draw capsules to visualize the position of the vertices
// in world coords
foreach(Vector3 v in worldVertices) {
GameObject g = GameObject.CreatePrimitive(PrimitiveType.Capsule);
g.transform.position = v;
}
}

9818649--1411095--EXAMPLE RESULT.jpg
9818649--1411095--EXAMPLE RESULT.jpg1362×934 143 KB

2

You’re doing TransformPoint twice on the vertex position for some reason. That’s going to negate any transform changes on the transform itself.

Also use code tags in future please: Using code tags properly

1 Like
3

Thanks for replying so quickly. Using TransformPoint twice indeed did not make much sense, I fixed that but still the result is the same. I’ll add the revised code with code tags here. Please let me know if you can find any other reason.

    // the plane to generate a grid on
    public GameObject currentMeshObject;

    // the mesh plane
    public Mesh currentMesh;

    // an array of vertices, that will contain all points on the plane in the plane's coord system
    public Vector3[] localVertices;

    // the plane's point transformed to the world coord system
    public List<Vector3> worldVertices;

    void GetWorldVertices()
    {
        // this will get all the mesh vertices (local coords)
        // then convert them to the world coordinates

        // get vertices based on the object's coordindate system
        localVertices = currentMesh.vertices;

        // transform them into the world coordinate system
        for (int i = 0; i < localVertices.Length; i++)

        {
            Vector3 localV = localVertices[i];
            Vector3 worldV = transform.TransformPoint(localV);
            worldVertices.Add(worldV);
        }

        // draw capsules to visualize the position of the vertices
        // in world coords
        foreach(Vector3 v in worldVertices) {
            GameObject g = GameObject.CreatePrimitive(PrimitiveType.Capsule);
            g.transform.position = v;
        }
    }


    // Start is called before the first frame update
    void Start()
    {
        currentMesh = currentMeshObject.transform.GetComponent<MeshFilter>().sharedMesh;
        GetWorldVertices();
    }
4

You should be calling TransformPoint on the transform of the currentMeshObject, not on the transform of the GameObject the script is attached to:

Vector3 worldV = currentMeshObject.transform.TransformPoint (localV);
2 Likes
5

Thank you both this works great!!