Accelerated and Extended Building of Implicit kd-Trees for Volume Ray Tracing
Implicit kd-trees have proven to greatly accelerate
iso-surface rendering by ray tracing, such that interactive
performance can already be achieved on
a dual processor machine. However, the kd-tree
could not be used for semi-transparent rendering
and building the kd-tree was still a slow process that
did not allow for rendering time-varying data sets.
In this paper we extend the kd-tree to provide
a coarse volume representation in addition to the
min/max values that allows to quickly skip homogeneous
regions. Additionally, we replace the recursive
build procedure by an iterative bottom-up
method distributed among several threads. These
extensions enable interactive rendering of semitransparent
and time-varying data sets.