Unity_MeshExtensions.css

using System;
using UnityEngine;

namespace _MyScripts.Utils
{
    public static class MeshExtensions
    {
        public static Mesh PivotToCenter(this Mesh originalMesh)
        {
            var mesh = new Mesh();
            mesh = originalMesh;

            var minX = float.MaxValue;
            var minY = float.MaxValue;
            var minZ = float.MaxValue;
            var maxX = float.MinValue;
            var maxY = float.MinValue;
            var maxZ = float.MinValue;

            //var shifts = new Vector3[mesh.vertexCount];
            //var firstVertex = mesh.vertices[0];
            
            for (var i = 0; i < mesh.vertexCount; i++)
            {
                var v = mesh.vertices[i];
                if (v.x > maxX) maxX = v.x;
                if (v.y > maxY) maxY = v.y;
                if (v.z > maxZ) maxZ = v.z;
                if (v.x < minX) minX = v.x;
                if (v.y < minY) minY = v.y;
                if (v.z < minZ) minZ = v.z;
                //shifts[i] = firstVertex - v;
            }

            var size = new Vector3(
                Math.Abs(minX) + maxX,
                Math.Abs(minY) + maxY,
                Math.Abs(minZ) + maxZ
            );
            var center = size / 2;

            var newVertices = new Vector3[mesh.vertexCount];
            for (var i = 0; i < mesh.vertexCount; i++)
            {
                var v = mesh.vertices[i];
                v -= center; // firstVertex;
                newVertices[i] = v;
            }
            mesh.SetVertices(newVertices);
            //Debug.Log(size + " " + center + " " + firstVertex + " - " + newVertices.First());

            return mesh;
        }

        public static Mesh PivotToCenterPoint(this Mesh originalMesh, Vector3 centerPoint)
        {
            var mesh = new Mesh();
            mesh = originalMesh;

            var minX = float.MaxValue;
            var minY = float.MaxValue;
            var minZ = float.MaxValue;
            var maxX = float.MinValue;
            var maxY = float.MinValue;
            var maxZ = float.MinValue;

            for (var i = 0; i < mesh.vertexCount; i++)
            {
                var v = mesh.vertices[i];
                if (v.x > maxX) maxX = v.x;
                if (v.y > maxY) maxY = v.y;
                if (v.z > maxZ) maxZ = v.z;
                if (v.x < minX) minX = v.x;
                if (v.y < minY) minY = v.y;
                if (v.z < minZ) minZ = v.z;
            }

            var newVertices = new Vector3[mesh.vertexCount];
            for (var i = 0; i < mesh.vertexCount; i++)
            {
                var v = mesh.vertices[i];
                v -= centerPoint;
                newVertices[i] = v;
            }

            mesh.SetVertices(newVertices);

            return mesh;
        }
    }
}