[vtkusers] vtkBox::IntersectBox

[David Doria]

> The "dir" is more than just a direction, its magnitude is important.
> It must be long enough to intersect the box. The documentation for the
> method is fairly clear on this point.
>
>  David
>

Haha that's a pretty loose definition of "clear" you're using there :)

I'm going to change it to say:
"Notes: the intersection ray dir[3] is NOT normalized. Valid
intersections will only occur between 0<=t<=1. That is, 'dir' also
encodes the length of the line segment which is used to do the
intersection in its magnitude."

Thanks David G.