Pilz/Pilz.Simple3DFileParser/Model/Mesh.cs

using System.Collections.Generic;
using global::System.Numerics;

namespace Pilz.S3DFileParser
{
    public class Mesh
    {
        public List<Vertex> Vertices { get; private set; } = new List<Vertex>();
        public List<Normal> Normals { get; private set; } = new List<Normal>();
        public List<UV> UVs { get; private set; } = new List<UV>();
        public List<VertexColor> VertexColors { get; private set; } = new List<VertexColor>();
        public List<Face> Faces { get; private set; } = new List<Face>();

        public void CenterModel()
        {
            CenterModel(new[] { this });
        }

        public static void CenterModel(IEnumerable<Mesh> meshes)
        {
            int avgX = 0;
            int avgY = 0;
            int avgZ = 0;
            long vertsCount = 0L;
            foreach (Mesh m in meshes)
            {
                foreach (Vertex v in m.Vertices)
                {
                    avgX = (int)(avgX + v.X);
                    avgY = (int)(avgY + v.Y);
                    avgZ = (int)(avgZ + v.Z);
                }

                vertsCount += m.Vertices.Count;
            }

            var avg = new Vector3(avgX, avgY, avgZ);
            avg /= new Vector3(vertsCount);
            foreach (Mesh m in meshes)
            {
                foreach (Vertex v in m.Vertices)
                {
                    v.X -= avg.X;
                    v.Y -= avg.Y;
                    v.Z -= avg.Z;
                }
            }
        }
    }
}