Calculating width, height and volume of atypical object

Question

I have atypical objects where I want to calculate its width, height and volume. For the sake of volume i have got this script

public class MeshVolume : MonoBehaviour
{
    void Start()
    {
        Mesh mesh = GetComponent<MeshFilter>().sharedMesh;
        float volume = VolumeOfMesh(mesh);
        string msg = "The volume of the mesh is " + volume + " cube units.";
        Debug.Log(msg);
    }


 public float SignedVolumeOfTriangle(Vector3 p1, Vector3 p2, Vector3 p3)
 {
     float v321 = p3.x * p2.y * p1.z;
     float v231 = p2.x * p3.y * p1.z;
     float v312 = p3.x * p1.y * p2.z;
     float v132 = p1.x * p3.y * p2.z;
     float v213 = p2.x * p1.y * p3.z;
     float v123 = p1.x * p2.y * p3.z;
     return (1.0f / 6.0f) * (-v321 + v231 + v312 - v132 - v213 + v123);
 }
 public float VolumeOfMesh(Mesh mesh)
 {
     float volume = 0;
     Vector3[] vertices = mesh.vertices;
     int[] triangles = mesh.triangles;
     for (int i = 0; i &lt; mesh.triangles.Length; i += 3)
     {
         Vector3 p1 = vertices[triangles[i + 0]];
         Vector3 p2 = vertices[triangles[i + 1]];
         Vector3 p3 = vertices[triangles[i + 2]];
         volume += SignedVolumeOfTriangle(p1, p2, p3);
     }
     return Mathf.Abs(volume);
 }

}

As I am not a mathematican so I can't verify that its is working fine and not but one thing is clear that it is not updating the volume calculation if i scale up or down the object. So is this the correct way to calculate object volume? Secondly, I am getting width and height of the object using meshRenderer bounds

Bounds meshBounds = GetComponent<MeshRenderer>().bounds;
float width = meshBounds.size.x;
float height = meshBounds.size.y;

Is this a correct approach for width and height calculation? How can I cross check it.

Answer 1

I have crossed check width and height and volume through revit tool.

For Width, Height and Breath::

Bounds meshBounds = GetComponent<MeshRenderer>().bounds;
float width   = meshBounds.size.x;
float height  = meshBounds.size.y;
float breath  =  meshBounds.size.z

In my case i have take MeshRendere bounds you can also calculate it through Collider.

For Volume:

public float SignedVolumeOfTriangle(Vector3 p1, Vector3 p2, Vector3 p3)
 {
     float v321 = p3.x * p2.y * p1.z;
     float v231 = p2.x * p3.y * p1.z;
     float v312 = p3.x * p1.y * p2.z;
     float v132 = p1.x * p3.y * p2.z;
     float v213 = p2.x * p1.y * p3.z;
     float v123 = p1.x * p2.y * p3.z;
     return (1.0f / 6.0f) * (-v321 + v231 + v312 - v132 - v213 + v123);
 }
 public float VolumeOfMesh(Mesh mesh)
 {
     float volume = 0;
     Vector3[] vertices = mesh.vertices;
     int[] triangles = mesh.triangles;
     for (int i = 0; i < mesh.triangles.Length; i += 3)
     {
         Vector3 p1 = vertices[triangles[i + 0]];
         Vector3 p2 = vertices[triangles[i + 1]];
         Vector3 p3 = vertices[triangles[i + 2]];
         volume += SignedVolumeOfTriangle(p1, p2, p3);
     }
     return Mathf.Abs(volume);
 }