.TH SG3d
.SH NAME
\fISG3d\fR        3 Dimensional Surface Renderer 
.br
.SH SYNOPSIS
\fBSG3d\fR
.br
\fBSG3d help\fR
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\fBSG3d\fR [\fB\-w\fR] [\fB\-z\fR] \fBelev=\fIname\fR \fBcolor=\fIname[,name,name]\fR 
   [\fBvector=\fIname\fR] [\fBsites=\fIname\fR] [\fB3dview=\fIname\fR] 
   [\fBscript=\fIname\fR] [\fBscolor=\fIname\fR]
.SH DESCRIPTION
\fISG3d\fR is a tool for viewing a data surface in three
dimensions using \fBGRASS\fR on \fISilicon Graphics IRIS\fR computers.  At 
startup, one graphics window and several interface windows are visible.
Other interface windows pop up when
their appropriate toggle button is selected from the \fIPanels\fR pull-down
menu.
To hide panels use the \fIClose\fR button at the bottom of each
pop-up panel; using the \fIQuit\fR or \fIClose\fR options from the
window manager's menu bar will cause the program to exit!
.SH "COMMAND LINE OPTIONS"
.LP
Flags
.IP \fI-w\fR
Enable writing to script files
.IP \fI-z\fR
Use site category as Z value (height) when displaying sites
.LP
Parameters
.IP \fIelev\fR
Raster file for Elevation
.IP \fIcolor\fR
Raster file(s) for Color (1 or 3 files).  
If three files are given, the first will be used for the red component, the second for the green component and the third for the blue component. 
When using three
files, each file must contain values in the range 0 - 255.
.IP \fIvector\fR
Vector overlay file
.IP \fIsites\fR
Sites overlay file
.IP \fIscolor\fR
Raster file for site category color
.IP \fI3dview\fR
3d viewing parameters file
.IP \fIscript\fR
Automatically run script file
.LP
If the user simply types \fISG3d\fR without specifying parameter
values on the command line, the program will prompt the user to enter these.
.SH NOTES
.LP
Environment variables \fISG3D_WIDTH\fR and \fISG3D_HEIGHT\fR  may be set
to define
the width and height (in pixels) of the graphics window at startup.
All \fISG3d\fR windows may be resized using the window manager's normal
controls at any time.  Text in the control panels is not scalable, however,
so the text will disappear if the panel is sized too small.
.LP
Before starting the program, check the 
resolution and
dimensions of the current \fBGRASS\fR region.  The  current resolution will determine the \fIbest\fR resolution
available in \fISG3d\fR.  For speed, the entire raster as defined by the
current region is loaded
into memory, along with vertex color and other surface information needed
for lighting calculations.  Thus, large regions such as 1000 rows x 1000
columns may cause memory problems.  \fISG3d\fR uses 12 bytes of memory for
each vertex, therefore a 1000 x 1000 raster would require 12 megabytes for
data alone.
.LP
The \fBGRASS\fR text window is used by \fISG3d\fR to issue prompts and 
warnings and to input filenames.  Therefore,
after starting the program, place the \fBGRASS\fR text window where it can
be seen and typed into.
.LP
Any sliders and dials used in the control panels have a FINE ADJUSTMENT:  
Hold down the \fBCtrl key\fR while manipulating the dial or slider for
fine control.
.LP
Full documentation detailing the action associated with each control is
available in the tutorial.
.SH BUGS
Sometimes very small holes will appear in the surface.  If they appear as points when drawing polygons with grid overlaid, the bug is in the Graphics Library 
and
it should be fixed in future versions of IRIX.  If the holes appear along an
edge of
a polygon, it is apparently due to the way non-planar polygons are interpreted.
In this case, drawing using the \fItriangulate\fR option should make the holes disappear.
.SH AUTHORS
Dave Gerdes and Bill Brown, U.S. Army Construction Engineering Research Laboratory
