cutting mesh

Hi All;

I'm very new in wpf and helix3d.
I have a 3d mesh model. The center of model positioned at Point3D(0,0,0). I want to cut the mesh which all vertices in positif Y axis.

  foreach (GeometryModel3D gm in mg.Children)
        {
            MeshGeometry3D mesh = (MeshGeometry3D)gm.Geometry;
            Point3DCollection positions = mesh.Positions;
            Vector3DCollection normals = mesh.Normals;
            Int32Collection indices = mesh.TriangleIndices;

            Point3DCollection newPositions = new Point3DCollection() ;
            Vector3DCollection newNormals = new Vector3DCollection();
            Int32Collection newIndices = new Int32Collection();
            int c = 0;
            foreach (Point3D p in positions)
            {
                if (p.Y >= 0)
                {
                    newPositions.Add(p);
                    newNormals.Add(normals.ElementAt(c)); //I'm not sure in this line
                    newIndices.Add(indices.ElementAt(c));
                }
                c++;
            }

            GeometryModel3D gd = new GeometryModel3D();
            MeshGeometry3D g = new MeshGeometry3D();
            g.Positions = newPositions;
            g.Normals = newNormals;
            g.TriangleIndices = newIndices;
            gd.Geometry = g;
            gd.Material = MaterialHelper.CreateMaterial(Colors.Aquamarine);
            nm.Children.Add(gd);
            nm.Transform = new TranslateTransform3D(new Vector3D(d.Bounds.X, d.Bounds.Y, d.Bounds.Z)); //translate to another positioned
        }
        ModelVisual3D v = new ModelVisual3D();
        v.Content = nm;

But i got the broken mesh. Any suggestions/ideas ?

Best Regards;
DM

Hi All;

I found the solution.

        var n = new Vector3D(0,0.2,1);
        var p = new Point3D(0, 0.5, 0);

            var geo = MeshGeometryHelper.Cut(mesh, p, n);
            var m = new GeometryModel3D(geo, gm.Material);
            m.BackMaterial = Materials.Red;
        var mv = new ModelVisual3D();
        mv.Content = m;
        view1.Children.Add(mv);

But i've another problem. When I added the manipulator (CombinedManipulator) to the ModelVisual3D object.
After rotating the mesh, I want to cut the mesh. But the cut direction still follow the mesh direction, not the viewport direction.

Any idea?

Hi All;

to precisely cut the mesh, i need to convert the model coordinate to global coordinate.

Regards;
DM