Earlier, we had welded the overlapping vertices along the neckline, to avoid duplicates, when two spline sections were combined together. Matters doesn't end there. We have similar duplicate candidates among segments also, that need to be removed. Switch the mode to 'Segment' in the modify panel in 3D Studio MAX ( 3ds max ), and select a segment along the neck line as shown in the figure. If you look closely, you will see that there is one more segment hidden beneath. Simply press Delete key to delete the unwanted overlapping segment in 3D Studio MAX ( 3ds max ). Repeat it along the neck line, so that only one segment remains between two vertices along the neck line in 3D Studio MAX ( 3ds max ).

Select the vertex near the front of the neck (selected in the figure), right click it and choose 'Weld Vertices' from the menu that appears in 3D Studio MAX ( 3ds max ). This will make the surface in that region smoother in 3D Studio MAX ( 3ds max ).