ShellSplatting is a direct volume rendering method that enables the
interactive rendering of anisotropic volumes. It is a combination of the
data structures of Shell Rendering with the rendering techniques of
Splatting, hence the name. It's simple to implement, works on generic
graphics hardware (anything with texturing and compositing should do the
trick), handles anisotropically sampled volumes and easily blends and
intersects with conventional geometry.
You can read the Eurographics / IEEE TCVG VisSym 2003 paper here (see this page for the full citation) and view the presentation slides here. For viewing the slides, you might want to activate "Smooth Line Art" in your PDF viewer (in Acroread, this is under Edit|Preferences|General) so that all the diagrams look their best. There are some diagrams in the presentation which do not appear in the paper, for instance one helping to explain the P and D data structures.
Here are the movies also referred to in the presentation.
They've all been compressed with the MS-MPEG4 codec (believe it
or not, for maximum quality and portability: this works on a default MS
Mediaplayer 6.4 or higher installation and also on all self-respecting
*ix mplayer installations; get codecs for MacOS X here) as AVI files.
|
2M movie demonstrating how one
normally goes about slicing through a volume. This is probably the
most basic way of visualising a 3D volume. |
|
800K movie showing interaction
with an isosurface that has been extracted from the same volume using
the marching cubes algorithm. |
| |
1.8M Div-X 4 movie showing a
good old software raycasting of the same volume. Of course it took
a few minutes (actually quite a few minutes) to generate all the frames
of this animation. |
|
850K movie showing a
ShellSplatting of the same volume. Note that it's being interacted
with in real-time. Well, you can see the exact figures in the
article and updated performance figures (for a GeForce4) in the
presentation. |
|
The good old engine block CT
dataset. The 2.4M AVI shows interaction with the ShellSplatted
volume rendering in high quality mode, fast mode and point mode. |
|
5.5M movie showing a
ShellSplatting of one of my favourite data sets. I really like
this one because it's so sparse, and the ShellSplatter of course
loves sparse volumes. |
|
4.6M movie showing some of the
specialities of the ShellSplatting algorithm. The scapula
(shoulder-blade) and slicing plane are rendered as normal opaque
geometry, whereas the thorax is rendered with the ShellSplatter.
Two things are important here: the direct volume rendering is
seamlessly blending and even intersecting with conventional geometry
and, more subtly, a binary segmented thorax is being rendered, but
without the usual stair-stepping effects that we expect. |