A bit more, including png images for two of four figures.

doc/iau208/partiview.tex

+% $Log$
+% Revision 1.1  2002/06/27 01:49:30  slevy
+% A bit more, including png images for two of four figures.
+%
+% Revision 1.1  2002/06/26 19:31:53  slevy
+% Maybe this will turn into an IAU208 paper about partiview.
+% Figures to appear in same partiview/doc/iau208 directory.
+%
+\documentstyle[11pt,newpasp,twoside,psfig]{article}
+\markboth{Author \& Co-author}{APS Conf. Ser. Style}
+\pagestyle{myheadings}
+\nofiles
+
+% Some definitions I use in these instructions.
+
+\def\emphasize#1{{\sl#1\/}}
+\def\arg#1{{\it#1\/}}
+\let\prog=\arg
+
+\def\edcomment#1{\iffalse\marginpar{\raggedright\sl#1\/}\else\relax\fi}
+\marginparwidth 1.25in
+\marginparsep .125in
+\marginparpush .25in
+\reversemarginpar
+
+\begin{document}
+\title{Publications of the Astronomical Society of the Pacific Conference Series---Instructions for Authors and Editors Using \LaTeX\ Markup}
+ \author{Stuart Levy}
+\affil{National Center for Supercomputing Applications, 
+        University of Illinois Urbana-Champaign,
+	605 E. Springfield,
+	Champaign, IL 61820}
+
+\begin{abstract}
+This paper describes partiview, a software tool for 
+interactive graphical display of collections of particles
+in 3-space, and its application in studying the results
+of N-body collisional stellar dynamics calculations from Starlab.
+\end{abstract}
+
+% ---
+
+\section{Introduction}
+Partiview is an interactive graphical software tool, focused on 
+flexible display of particles in 3-space.
+
+Input data to partiview is provided as a (possibly time-varying)
+collection of particles, each with a 3-D position and an arbitrary number
+of other floating-point attributes ("fields"), and a configuration script
+specifying which fields to map into visible properties,
+including color and luminosity.  For example, if a field were named Tlog,
+   color Tlog 3.2 4.5
+assigns colors by using the Tlog field as an index into a
+user-supplied color table via a linear mapping
+that associates 3.2 and 4.5 with the colormap's endpoints.
+Text-based commands can change these selections interactively,
+switching between coloring galaxies by e.g. morphological type,
+local density, or group membership on the fly.
+
+From each particle's luminosity and distance from the current
+viewpoint, partiview draws a dot whose screen brightness and size
+suggest its computed apparent brightness.  With dots up to a few
+pixels across, apparent brightness may usefully range by several
+hundredfold, and larger ranges can be suggested by adding textured
+polygons -- "haloes" -- whose size varies similarly.  The result
+is good enough to give plausible naked-eye starfields given a table
+of stellar luminosities, colors and 3-D positions as in Figure 1,
+drawn using Hipparcos data.
+
+
+This sort of viewpoint-dependent apparent brightness
+is a feature that few other scientific visualization
+packages don't seem to offer, even though it's
+inexpensive to compute and can be useful.
+(Where not useful, as when making orthographic
+plots of 3-D scenes, it can be switched off in partiview.)
+
+Some simple database-like operations are provided.
+For example, one can display only the subset of particles where
+some (single) field has values in a given range or set,
+or look only at particles lying within a given rectangular subvolume,
+Also one can print a histogram of values of a field,
+over all particles or the selected subset.
+
+\section{Desktop and dome}
+The same graphical and data-handling code is embedded
+in multiple guises for different computing environments.
+Both accept the same data and configuration files, and most of the same
+text-based interactive commands.  Figure 1 illustrates the
+desk- (or lap-)top version, mouse and keyboard driven
+with conventional buttons and sliders for common controls,
+available for Unix-like systems and for Windows.
+Figure 2 shows the virtual-reality version,
+built using the Virtual Director virtual-choreography framework
+and the CAVE library; it can run on Silicon Graphics computers
+with multiple graphics pipes.
+
+Though the latter was originally written for the
+CAVE virtual reality room at NCSA, it is used elsewhere too.
+The Hayden Planetarium at the American Museum of Natural History
+in New York built a Silicon Graphics-driven display for their
+planetarium dome; this turned out sufficiently
+CAVE-like that the same software runs in the Hayden dome and is
+regularly used there.
+
+
+\section{N-body dynamics: examining Starlab traces}
+
+Stellar dynamics simulations done in Starlab [ref?]
+produce "traces", recording various information about each star
+as a function of time: physical properties such as mass,
+luminosity and temperature; state vectors with time derivatives up to jerk;
+and hierarchical descriptions of interacting groups.
+
+Partiview, coupled with the Starlab libraries to read and interpolate
+traces, is adapted to display these properties as shown in
+% primbin16
+Figures 3 and 4.
+
+\begin{figure}
+\psfig{figure=primbin16.ps,height=2.5in}
+\caption{Interacting groups of stars from Starlab, with hierarchy shown.
+Tick marks on each segment (a) mark center-of-mass position and (b)
+have length proportional to true, not projected, separation of that pair of nodes.}
+\end{figure}
+
+Each star's dynamical state is sufficiently finely sampled in time
+to allow accurate interpolation, generally at some fixed multiple of the
+internal simulation timestep.   Thus stars in dense regions
+may have far more frequent trace entries than isolated stars.
+The Starlab libraries offer functions to interpolate the state of the
+simulation at any time.
+
+\end{document}