More written.

doc/iau208/partiview.tex

 % $Log$
+% Revision 1.2  2002/06/28 01:41:59  slevy
+% More written.
+%
 % Revision 1.1  2002/06/27 01:49:30  slevy
 % A bit more, including png images for two of four figures.
 %
@@ -24,7 +27,7 @@
 \reversemarginpar
 
 \begin{document}
-\title{Publications of the Astronomical Society of the Pacific Conference Series---Instructions for Authors and Editors Using \LaTeX\ Markup}
+\title{Interactive 3-D visualization for particle systems with Partiview}
  \author{Stuart Levy}
 \affil{National Center for Supercomputing Applications, 
         University of Illinois Urbana-Champaign,
@@ -40,7 +43,7 @@ of N-body collisional stellar dynamics calculations from Starlab.
 
 % ---
 
-\section{Introduction}
+\section{Partiview}
 Partiview is an interactive graphical software tool, focused on 
 flexible display of particles in 3-space.
 
@@ -49,7 +52,8 @@ 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
+{\verb"  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.
@@ -64,10 +68,9 @@ 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,
+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
@@ -82,15 +85,45 @@ 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.
 
+\begin{minipage}{3.5in}
+	\centerline{\hbox{
+	\psfig{figure=starfield.ps,height=2.7in}
+	}}
+	\centerline{Figure 1. Partiview showing star field from Hipparcos data with 
+		Sun at upper left, marked by 0.1 pc crosshair.}
+\end{minipage}\    \
+\begin{minipage}{3.5in}
+	\centerline{\hbox{
+	\psfig{figure=galaxies.ps,height=2.7in}
+	}}
+	\centerline{Figure 2.  Virtual Director version.}
+\end{minipage}
+
+
+% \begin{minipage}{3.5in}
+%   \begin{figure}
+%    \psfig{figure=starfield.ps,height=2.7in}
+%    \caption{Star field from Hipparcos data.  The Sun is
+%     at upper left, and the crosshair has radius 0.1 pc.}
+%   \end{figure}
+% \end{minipage}\    \   
+% \begin{minipage}{3.5in}
+%   \begin{figure}
+%    \psfig{figure=galaxies.ps,height=2.7in}
+%    \caption{Galaxies.}
+%   \end{figure}
+% \end{minipage}
+
+
 \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
+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,
+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.
@@ -109,13 +142,31 @@ regularly used there.
 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.
+luminosity and temperature; position and three time derivatives;
+and hierarchical descriptions (binary trees) 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.
+traces, is adapted to display these properties as the cluster evolves.
+Figure~3 shows a tiny test case, comprising 16 stars.  Bound or
+strongly-interacting systems are circled[[, and colored according to the
+number of members of the group]].  Circle sizes are related
+to separation or semimajor axis, but can be constrained to a range
+of screen sizes to ensure that even tightly-bound systems are always
+visibly marked.   Groups' binary trees, with stars as leaves and
+center-of-mass points as nonleaf nodes, are shown as stick figures.
+Tick marks perpendicular to the tree edges, drawn in the screen plane,
+serve a dual purpose: their positions show the center-of-mass location,
+and their lengths are proportional to the instantaneous true separation
+of the nodes on that edge.  
+Thus in the triple system [[in magenta]], although in this view the
+lower-right pair of stars seem very close together, this must be a 
+projection effect; as shown by the tick marks, their true separation
+is nearly as large as that from their center-of-mass to the upper-left star.
+
+Figure~4 shows a larger cluster evolving in a tidal field
+[[with stars colored by mass]].  "Trails" show the recent motion
+history of each star, so long trails show high speed, and curved ones
+high acceleration.  Note the tidally escaping stars at left and right.
 
 \begin{figure}
 \psfig{figure=primbin16.ps,height=2.5in}
@@ -124,6 +175,11 @@ 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}
 
+\begin{figure}
+\psfig{figure=0607.ps,height=2.5in}
+\caption{Star cluster dispersing in a tidal field}
+\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