  Intersection algorithms are very important in computation of geometrical
problems. Algorithms for a line intersection with linear or quadratic surfaces
are quite efficient. However, algorithms for a line intersection with other
surfaces are more complex and time consuming. In this case the object is
usually closed into a simple bounding volume to speed up the cases when the
given line cannot intersect the given object. In this paper new formulations of
the line-torus intersection problem are given and new specification of the
bounding volume for a torus is given as well. The presented approach is based
on an idea of a line intersection with an envelope of rotating sphere that
forms a torus. Due to this approach new bounding volume can be formulated which
is more effective as it enables to detect cases when the line passes the "hole"
of a torus, too.
