README file for alvis (3D ALPHA-SHAPE VIEWING SOFTWARE)
Version 0.95


1. Read "Abstract" for a brief description of the concept of 3D alpha
   shapes.


2. Read "Copyright" for copyright information on this software.

** IMPORTANT NOTE: If you use this program and can think of possible
** applications of 3D alpha shapes, we would really like to hear about
** it.  Please send a short note to <pfu@ncsa.uiuc.edu> briefly
** describing what you do and where you could use alpha shapes.  Also,
   any interessting (real life) data sets would be highly appreciated.
** The more feedback we get, the higher is the probablility that we can
** continue this project!


3. Read "Tutorial" for an informal description of the programs.

   (The tutorial is definitely no substitute for a documentation,
    but is the best you can get right now. :-)


3. Type "alvis -help" for command-line arguments.

If the environment variable ALVIS_OPTIONS is defined, alvis reads this
string before the command-line arguments; eg:

   setenv ALVIS_OPTIONS ' -C "singular 0.8 0 0" -G "pixel 20 664 510 994" '


4. Misc commands:

Click the "misc" button in the alvis panel and type in the misc command
via keyboard.  The <BACKSPACE> key works as expected.  The <ENTER> key
terminates the input and executes the command.  To cancel a command type
<BACKSPACE> until the input line is empty.  (Sorry! :-)  Clicking "misc"
while the program is executing a command, serves as an interrupt.

> do [-a <value>] [<number>] -d <dump.file> [-A] [-DTU]

        <number> ......... number of shapes (upper bound with -U)
        -a <value> ....... set specific alpha-value
        -U ............... unique probes per alpha-interval
        -D ............... dryrun
        -d <dump.file> ... dump shape to <dump.file>
        -A ............... append to <dump.file>
        -T ............... dump tetrahedra, too (only with face list)

                <dump.file>     *.FL ... ASCII face list
                                *.NL ... ASCII number list (one line per shape)
                                *.rgb .. (not yet implemented!)

> dump <path>

        will dump the graphics window to <path>.rgb in SGI .rgb format,
        plus, some some info in file <path>.info

> option [-v] [-B "<x> <y> <z>"] [-B off]

        -v ... toggle compute_volume_etc flag
        -B ... ball eraser (hack)


5. *.FL File (face list)

The file contains ASCII text.  The format is line-oriented, where the
first character in a line tells you what's there:

        # text          header-line with some (self-explanatory) info;
                        header information includes, among others,
                        alpha-value and number of faces in face list;
                        such header-lines also serve as delimiters between
                        face lists of different shapes

        T %d %d %d %d   tetrahedron of regular interior
                        (indices refer to vertices in data file)

        F %d %d %d      triangle on regular boundary; positively oriented,
                        ie, the "top" of the normal vector sees the three
                        vertices making a CCW-turn; and this normal vector
                        points to the "outside" of the shape
        
        f %d %d %d      triangle on singular boundary; normal vectors in
                        both directions point to the "outside" since such
                        triangle is isolated

        e %d %d         edge on the singular boundary, ie, isolated edge

        v %d            vertex on the singular boundary, ie, isolated vertex


6. *.NL File (number list)

The file contains ASCII text.  One line per shape is generated, containing
important feature numbers...

Contact:
	Ping Fu 	pfu@ncsa.uiuc.edu
	Ernst Mucke	mucke@cs.uiuc.edu
