More Alignment Tools Continued

6. Pulling Points 

Up until now, the reason for having a "grid" of surfaces that align has not been obvious. When we begin to manipulate points on a surface to align with other points on adjacent surfaces, you can see why we use this approach.

Other software packages use functions that "stitch" adjacent surfaces together. By pulling points to match points on other surfaces, we can create very tight seams between surfaces.

If you look at a NURBS surface with the hulls displayed, you can determine the number of hulls by counting the number of spans in the surface, and adding 2. The additional 2 hulls occur at the sides of the surface. Because we are creating a "grid" where edges of surfaces line up with the adjacent edges of surfaces, we can snap points from one surface exactly to points of the adjacent surface.

It is important to note that the alignment tools described above do not completely fix alignment on the "five-cornered intersection". The "Attach-Detach" will work most of the way, but sometimes "You just gotta pull points".

The technique used below shows how to pick 5 points on 5 adjacent surfaces, use the "Center Pivot" plug in to set the pivot point of the selected points, then scale to zero to snap the point to one central point. The rest of the points that need to be closed are adjusted the same way.
Point Scaling Condition After Scaling
points 1 pulling points 2

7. View Move Plugin

Just because you have pulled points to get seams tight, does not mean that you have created a nice blended transition.

One of the most important plug-ins that you can get is the "view-move" plug-in. This plug-in allows you to rotate around in the perspective window and move the CV's relative to the view that you are in. Things to be careful about when using the view-move plug-in are:

1. The perspective view can fool you. Become familiar with the undo function in the plug-in (Control ->Left Mouse Click) Always check your placement after moving the CV.

2. Be sure that you get out of "View Move" mode by selecting another tool every time you are done using it. View Move can create some really bad results if you get sloppy with it.