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    1 \chapter{PERIPHERAL DEVICES}
    2 
    3 Before we discuss the features of MGED, we will introduce
    4 the hardware devices used to implement them.
    5 These devices are the ``tools of the trade'' for the MGED user.
    6 We will discuss only basic operational characteristics here.
    7 Specific use of these devices will be covered in the later sections
    8 on the viewing and editing features of MGED.
    9 
   10 \section{Joystick}
   11 
   12 The joystick is a mechanical device used to do rotations in MGED.
   13 Any movement left or right rotates the display about the
   14 X-axis.  Any movement up or down rotates the display
   15 about the Y-axis.  When the joystick top is twisted in a clockwise or
   16 counterclockwise direction, the display rotates about the Z-axis.
   17 Any combination motion of the joystick will produce a ``combined''
   18 rotation about the appropriate axes.
   19 As implemented on the Vector General hardware,
   20 all of these motions have a spring return to a null center position.
   21 
   22 \section{Button Box}
   23 
   24 The button box contains a collection of buttons.
   25 On each button is a light that can be lit under program control.
   26 Pressing a button sends a ``press'' event to MGED,
   27 and results in an action occurring, or a condition being set.
   28 The exact functions assigned to these buttons will be discussed
   29 in the sections on viewing the display and on editing.
   30 
   31 \subsection{Vector General Buttons}
   32 
   33 \begin{figure}
   34 \centering \includegraphics{fig-vg-buttons.ps}
   35 \caption{Vector General Button Assignments}
   36 \label{vg-buttons}
   37 \end{figure}
   38 
   39 \begin{figure}
   40 \centering \includegraphics{fig-sgi-buttons.ps}
   41 \caption{Silicon Graphics Button Assignments}
   42 \label{sgi-buttons}
   43 \end{figure}
   44 
   45 % \gluein 4.5in by 4.5in, Vector General Button Assignments, vg-buttons.
   46 % XXX \gluein 4.5in by 4in, Megatek Dial and Button Box, mg-buttons.
   47 The Vector General has thirty-two buttons.
   48 Figure \ref{vg-buttons} depicts the functions programmed
   49 for each button.
   50 The buttons in the shaded area are used for editing while the
   51 rest are used for viewing the display.
   52 
   53 \subsection{Megatek Buttons}
   54 
   55 \begin{figure}[tbp]
   56 \begin{tabular}{rl}
   57 Button  & Function\\
   58  \\
   59 1       & View Mode:  Restores View \\
   60         & Edit Mode:  Translation in the Object-Edit mode \\
   61 2       & View Mode:  Saves View \\
   62         & Edit Mode:  Translation in the Object-Edit mode \\
   63 3 \\
   64         & Edit Mode:  Saves the model being displayed on the screen \\
   65 4       & Off:        Viewing mode \\
   66         & On:         Edit mode \\
   67 5       & View Mode:  Resets View \\
   68         & Edit Mode:  Scaling in the Object-Edit mode \\
   69 6 \\
   70         & Edit Mode:  Rotation in the Object-Edit mode \\
   71 7       & View Mode:  Angle/Distance Cursor \\
   72         & Edit Mode:  Translation in the Object-Edit mode \\
   73 8 \\
   74         & Edit Mode:  Rejects display and returns to Viewing display \\
   75 9       & View Mode:  Bottom View \\
   76         & Edit Mode:  Scaling in the Solid-Edit mode \\
   77 10      & View Mode:  Left View \\
   78         & Edit Mode:  Rotation in the Solid-Edit mode \\
   79 11      & View Mode:  Rear View \\
   80         & Edit Mode:  Translation in the Solid-Edit mode \\
   81 12      & View Mode:  90, 90 View \\
   82         & Edit Mode:  Restores Edit mode menu \\
   83 13      & View Mode:  Top View \\
   84         & Edit Mode:  Transfers from Viewing to Solid Pick \\
   85 14      & View Mode:  Right View \\
   86         & Edit Mode:  Transfers from Viewing to Object Pick \\
   87 15      & View Mode:  Front View \\
   88  \\
   89 16      & View Mode:  35/45 View
   90 \end{tabular}
   91 \caption{Megatek Buttons \label{mg-button-table} }
   92 \end{figure}
   93 
   94 The Megatek button box
   95 is a general purpose input/output device that communicates with
   96 MGED through an intelligent control unit.  The device has eight
   97 rotatable knobs and 16 buttons with lights.
   98 % XXX See Figure \ref{mg-buttons}.
   99 The ``buttons'' and ``knobs'' of the Megateks are located in the same box.
  100 There are not enough buttons to have just one assigned meaning, hence
  101 most buttons have dual functions.
  102 To toggle the functions of the buttons,
  103 use the upper right button (toggle button).
  104 When the light on this button is ON, the functions listed on the RIGHT above
  105 each button is the current function.
  106 When the light on the ``toggle'' button is OFF, the functions labeled on the
  107 LEFT are then in effect.
  108 The left/right meaning of these buttons is grouped generally according to
  109 viewing functions on the left and editing functions on the right.
  110 
  111 Figure \ref{mg-button-table}
  112 summarizes the uses of the buttons.
  113 Depressing the button switches the light on and off.  Many of these serve a
  114 dual role depending upon the selected mode - viewing or editing.  The mode is
  115 selected by depressing button 4.  If light 4 is off, the system is performing
  116 in the viewing mode, and the commands shown in the top half of the table are
  117 executed.  If light 4 is on, the system is performing in the edit mode, and
  118 the commands shown in the bottom half are executed.
  119 
  120 \subsection{Silicon Graphics Buttons}
  121 
  122 The button box layout for the SGI Iris is given
  123 in Figure \ref{sgi-buttons}.
  124 Note that the ``right'' button shows you the right side of the
  125 model, as if you were looking in from the left.
  126 To achieve the customary draftsman views, this function
  127 goes on the left.
  128 
  129 The upper left button is the {\bf help} key.
  130 If this button is held down, and any other button (or knob)
  131 is activated, a descriptive string is displayed in the eight character
  132 LED display on the button box.
  133 The upper right button is used to reset all the knobs to zero.
  134 This is useful to halt a runaway rotation or zoom operation.
  135 
  136 %\begin{figure}[tbp]
  137 %{\tt \begin{verbatim}
  138 %          |---------|---------|---------|---------|
  139 %          |         |         |         |  Zero   |
  140 %          |  Help   |   ADC   | Reset   |  Knobs  |
  141 %|---------|---------|---------|---------|---------|---------|
  142 %|   Obj   |   Obj   |   Obj   |   Obj   |         |  Save   |
  143 %|  Scale  | ScaleX  | ScaleY  | ScaleZ  | empty   |  View   |
  144 %|---------|---------|---------|---------|---------|---------|
  145 %|   Obj   |   Obj   |   Obj   |   Obj   |         | Restore |
  146 %| TransX  | TransY  | TransXY | Rotate  | empty   |  View   |
  147 %|---------|---------|---------|---------|---------|---------|
  148 %|  Solid  |  Solid  |  Solid  |  Solid  |   Obj   | Solid   |
  149 %|  Trans  |   Rot   |  Scale  |  Menu   |  Pick   | Pick    |
  150 %|---------|---------|---------|---------|---------|---------|
  151 %| REJECT  | Bottom  |  Top    |  Rear   |  90,90  | ACCEPT  |
  152 %|---------|---------|---------|---------|---------|---------|
  153 %          |  Right  |  Front  |  Left   |  35,25  |
  154 %          |---------|---------|---------|---------|
  155 %\end{verbatim} }
  156 %\caption{Silicon Graphics Button Layout \label{XXsgi-buttons} }
  157 %\end{figure}
  158 
  159 \section{Knobs (Dials)}
  160 
  161 The knobs (or control dials) are used to send digital information
  162 to the computer.
  163 As a knob is turned, a succession of numbers are available for
  164 use by the computer.
  165 The knobs can be used to rotate a displayed object about the x, y, or z
  166 axis, translate the object along the x or y axis, and change the size of the
  167 view.  Action performed by these knobs is continuous and is initiated by
  168 turning the knob in the proper direction and terminated by turning the knob
  169 in the opposite direction.
  170 
  171 \subsection{Vector General Knobs}
  172 
  173 \begin{figure}
  174 \centering \includegraphics{fig-vg-knobs.ps}
  175 \caption{Vector General Knob Assignments}
  176 \label{vg-knobs}
  177 \end{figure}
  178 
  179 \begin{figure}
  180 \centering \includegraphics{fig-sgi-knobs.ps}
  181 \caption{Silicon Graphics Knob Assignments}
  182 \label{sgi-knobs}
  183 \end{figure}
  184 
  185 % \gluein 4.5in by 3.5in, Vector General Knobs, vg-knobs.
  186 % \gluein 4.5in by 3.5in, Silicon Graphics Knobs, sgi-knobs.
  187 Figure \ref{vg-knobs} depicts the functions assigned to each of the ten knobs.
  188 The exact functions of each of these knobs will be discussed in
  189 the angle distance cursor section and in the viewing features section.
  190 
  191 \subsection{Megatek Knobs}
  192 
  193 The ``buttons'' and ``knobs'' of the Megateks are located in the same box.
  194 % XXX as shown in Figure \ref{mg-buttons}.
  195 There are not enough knobs to have ONE assigned meaning, hence
  196 three knobs have dual functions.
  197 The second function of the first three knobs is only in effect when
  198 the angle-distance cursor (ADC) is on the screen.
  199 
  200 \subsection{Silicon Graphics Knobs}
  201 
  202 Figure \ref{sgi-knobs} depicts the functions assigned to the
  203 eight knobs on the Silicon Graphics knob box.
  204 In normal operation, the left knobs provide rotations,
  205 and the right knobs provide translations and zooming.
  206 When the angle/distance cursor is activated, some of the
  207 knobs are redefined.
  208 
  209 \section{Mouse or Data Tablet}
  210 
  211 Moving the mouse or the data tablet ``pen'' causes a cursor
  212 on the screen to move.
  213 The screen X-Y coordinates of the cursor can be sensed by MGED
  214 at any time.
  215 Clicking one of the mouse buttons,
  216 or depressing the tip of the pen, results in MGED receiving
  217 a special event notification.
  218 The meaning of this mouse event depends on the current editing mode
  219 and which portion of the display faceplate that the cursor is located
  220 in.
  221 
  222 Below is a list of some of the functions the mouse is used for in MGED;
  223 \begin{itemize}
  224 \item
  225 Selecting editing menus, edit functions (move faces, move edges
  226 etc.) and viewing functions (selected from main edit menu); move
  227 pointer to appropriate edit function and press center mouse button.
  228 \item
  229 Pointing functions; interactively positioning solid primitive
  230 relative to other solids with positioning or size update being
  231 displayed at the same time, position pointer where required and click
  232 center mouse button.
  233 \item
  234 Scaling of view size; enlarge or reduce for a more detailed view of
  235 object, left button shrinks view size, right button enlarges view
  236 size.
  237 \item
  238 During the solid or object illuminate phase of editing,
  239 the screen is divided into
  240 invisible horizontal sections.
  241 The available selections are scanned by moving the mouse up and down.
  242 \item
  243 When MGED is is the viewing state,
  244 and a mouse event is received which is not in the menu area of the faceplate,
  245 the point at which the cursor is pointing at will be translated to become
  246 the center of the current view.
  247 By pointing and clicking the center mouse button,
  248 the center of the viewing cube
  249 can be moved to allow close-up viewing of different areas in your
  250 model.
  251 \end{itemize}
  252 
  253 \subsection{Vector General Data Tablet}
  254 
  255 Position information is entered using a pen-like stylus.
  256 The distance this pen is from the tablet is important.
  257 If the pen tip is within one half inch of the tablet surface, the cursor
  258 location on the screen corresponds to the X,Y location of the
  259 pen on the tablet.  This condition is called the ``near'' position.
  260 If the pen is more than one half inch from the tablet surface, the
  261 cursor remains located in the center of the screen.
  262 When the pen is pressed against the tablet surface,
  263 the pressure switch is activated and a ``mouse'' event
  264 is sent to MGED.
  265 
  266 \subsection{Megatek Data Tablet}
  267 
  268 Some Megatek systems enter position data on the data tablet
  269 using a pen-like stylus.
  270 If the tip of the stylus is
  271 within one-half inch of the surface of the tablet, a ``star'' corresponding
  272 to this location is displayed on the display screen.  If the tip is moved
  273 more than one-half inch from the surface, the position of the star remains
  274 fixed.  When the stylus is pressed against the tablet surface, the pressure
  275 switch is activated and a ``mouse'' event is sent MGED.
  276 
  277 Other Megatek data tablets have a mouse instead of a pen.
  278 This mouse has four buttons on it.
  279 The yellow (top) button is used during illumination and editing just as the
  280 pen on the Vector General terminals.
  281 However, in the viewing mode, when pushed, the point which it was pointing
  282 at will be drawn at the center of the screen.
  283 The blue (bottom) button has this same function at ALL times and is used
  284 to ``slew'' the display during editing.
  285 The white (left) and the green (right) buttons on the mouse are used for
  286 zooming the display at a fixed rate.
  287 The white button will zoom out and the green button will zoom in.
  288 
  289 \subsection{Silicon Graphics Mouse}
  290 
  291 The left and right mouse buttons are used for binary (2x) zooming,
  292 and the center mouse button is used for all other MGED mouse functions.
  293 
  294 On the Silicon Graphics 3-D workstations, MGED can be run directly,
  295 or it can be run under the window manager MEX.  In both cases,
  296 MGED opens two windows, one outlined in white for all text interaction,
  297 and one outlined in yellow for all graphics display.
  298 When running MGED directly (without MEX), all mouse events are
  299 sent the MGED, regardless of where the mouse is pointing.
  300 In order to shift emphasis between the graphics and text windows,
  301 the smaller one can be enlarged by pointing the cursor within the
  302 boundaries of the smaller window, and pressing the center button.
  303 This enlarges that window, and reduces the size of the other window.
  304 
  305 When MEX is running, it is necessary to follow the MEX convention of
  306 moving the cursor into the desired window, and clicking the right mouse
  307 button, to ``attach'' all input to that window.
  308 This has the unfortunate consequence of requiring a lot of extra
  309 mouse clicking, because the graphics window needs to be attached
  310 when using the buttons, knobs, and mouse, while the text window
  311 needs to be attached in order to enter keyboard commands.
  312 
  313 On the Silicon Graphics 4-D workstations running 4Sight,
  314 mouse events are sent to MGED only when the cursor is within the
  315 boundaries of the MGED graphics window.
  316 
  317 \subsection{Sun Workstation Mouse}
  318 
  319 On the Sun workstation, MGED must be run in a {\bf suntools} window.
  320 The main consequence of this is that mouse events are sent to MGED
  321 only when the cursor is within the boundaries of the MGED graphics window
  322 on the screen.
  323 The left and right mouse buttons are used for binary (2x) zooming,
  324 and the center mouse button is used for all other MGED mouse functions.
  325 
  326 \section{Keyboard}
  327 
  328 The keyboard is used to issue commands and supply parameters to MGED.
  329 It is also used to login and logout of the UNIX system, and to
  330 run other UNIX programs.
  331 All characters typed on the keyboard,
  332 with the exception of the user's password, are displayed (echoed) on the
  333 monitor.
  334 In this text, all input typed by the user is
  335 shown in {\em italics}, while all literal MGED output
  336 is shown in {\tt typewriter font}.
  337 All entries are
  338 terminated by depressing the RETURN key.
  339 This action immediately precedes the execution of the directive.
  340 In most cases, lower case letters
  341 must be used.  A space must be used between the command and its
  342 arguments.
  343 Embedded blanks are not allowed.
  344 Entering Control/H causes cursor to backspace and erase entered
  345 information.
  346 An MGED command is interrupted by entering Control/C.
  347 End-of-File is sent to MGED by entering Control/D.
  348 The graphics editor displays the prompt
  349 \begin{verbatim}
  350     mged>
  351 \end{verbatim}
  352 on the display whenever it is ready to accept a command from the keyboard.
  353 
  354 \chapter{OPERATING INSTRUCTIONS}
  355 
  356 \section{Entering the Graphics Editor}
  357 
  358 Type {\em mged filename}, e.g.:
  359 \begin{verbatim}
  360      mged s_axle.g
  361      mged shaft.g
  362      mged fred.g
  363 \end{verbatim}
  364 where the filename is the name of the UNIX file in which
  365 your object description data is stored.
  366 It is conventional that the
  367 extension ``.g'' on the filename
  368 signifies a graphics file, and is a good practice, but is not required.
  369 If the named database does not already exist,
  370 MGED will ask if it should create a new database.
  371 MGED will ask:
  372 
  373 {\tt \begin{verse}
  374 \% {\em mged new.g} \\
  375 BRL-CAD Release 3.0 Graphics Editor (MGED) \\
  376 \ \ \ \ Tue Sep 6 02:52:55 EDT 1988 \\
  377 \ \ \ \ mike@video:/cad/mged.4d \\
  378 new.g: No such file or directory \\
  379 Create new database (y|n)[n]? {\em y} \\
  380 attach (nu|tek|tek4109|ps|plot|sgi)[nu]? {\em sgi} \\
  381 ATTACHING sgi (SGI 4d) \\
  382 Untitled MGED Database (units=mm) \\
  383 mged>
  384 \end{verse} }
  385 Here, the {\em italic} type indicates the user's response:
  386 {\em y} instructs MGED to create the new database, and
  387 {\em sgi} instructs MGED to attach to a window
  388 on the Silicon Graphics (SGI) workstation.
  389 
  390 Directives to the graphics editor are made by
  391 \begin{enumerate}
  392 \item entering information from the keyboard,
  393 shown here in the text by the use of {\em italics},
  394 \item using the stylus to select items from
  395 the menu (select), and
  396 \item pressing buttons and twisting knobs on the
  397 function control box (press, twist).
  398 \end{enumerate}
  399 
  400 The prompt for a command is {\tt mged>}.
  401 
  402 \subsection{Running MGED on a Silicon Graphics}
  403 
  404 When running MGED from the console of a Silicon Graphics workstation,
  405 MGED retains the text window from which it was started,
  406 and opens a second window for the graphics display.
  407 By default, the graphics window is quite large, and the text window
  408 is rather small.
  409 
  410 On the SGI 3-d workstations,
  411 should you wish to have a large text window to scan printed output, move
  412 the mouse pointer into the text window and click the center mouse button.
  413 Use the reverse procedure to regain a large graphics window, i.e.,
  414 move the mouse pointer into the graphics window
  415 and click the center mouse button.
  416 
  417 \subsection{Running MGED on a Tektronix}
  418 
  419 To run MGED on the tek4014 class of terminals one needs to have TWO
  420 terminals - the graphics terminal (4014 or one which emulates a 4014) and
  421 another terminal to enter commands on.
  422 
  423 The procedure is as follows:
  424 \begin{enumerate}
  425 \item login on the graphics terminal
  426 \item enter {\em tty} to find out which terminal number has been assigned
  427 \item  enter {\em sleep 32000} to put the graphics terminal in sleep mode
  428 \item  login on the other terminal
  429 \item  enter {\em mged file} to execute MGED
  430 \item  enter {\em tek} to select the tek4014 device processor
  431 \item  enter the tty value found in step 2.
  432 \item  perform editing
  433 \item  enter {\em q} to quit MGED
  434 \item  enter control-c on the graphics terminal to end the sleep mode
  435 \item  logout on both terminals
  436 \end{enumerate}
  437 
  438 Since there are no knobs or buttons on the tek4014 class of terminals, one
  439 is forced to use the {\em press} and {\em knob} commands to emulate these
  440 peripherals.
  441 Other commands which can/should be used are:
  442 
  443 \begin{tabular}{rl}
  444 ill     & put up a desired path \\
  445 center  & slew the display \\
  446 size    & zoom the display \\
  447 sed     & solid edit immediately
  448 \end{tabular}
  449 
  450 The main force behind the writing of a driver for the tek4014 terminals
  451 was to allow the use of the Teletype 5620 terminals.
  452 These graphic terminals have an internal processor and different windows
  453 can be set up which represent different terminals.
  454 Hence two terminals are NOT necessary.
  455 The use of the Teletype 5620 terminals is then the same as the procedure
  456 outlined above, except each window represents a terminal.
  457 
  458 \section{The Pop-Up Button Menu}
  459 
  460 The default MGED faceplate is shown in Figure \ref{faceplate}.
  461 If the BUTTON MENU area on the screen is selected with the mouse,
  462 then the pop-up button menu appears, as shown in Figure \ref{buttonmenu}.
  463 This menu can be very useful in reducing the amount of hand motion
  464 between the mouse and the button box.
  465 
  466 \section{Starting Your Model}
  467 
  468 Modeling practices using MGED can be quite individual.  The following is a
  469 suggested modeling method to start with; you may end up developing your own
  470 style as you become more familiar with MGED.
  471 
  472 First of all, decide how you want to represent your model, including the
  473 amount of detail, types of solids and regions necessary.  Have an accurate
  474 sketch or engineering drawing available, so that you can easily transfer its
  475 information into the types of primitive solids necessary to create your model.
  476 Where possible it is recommended to start with a large block solid and
  477 ``subtract'' pieces from it.  In this way you avoid errors with abutting
  478 faces of a collection of solids ``unioned'' together.
  479 
  480 Next the solids are created using the
  481 {\em make}, {\em cp}, {\em mirror} or {\em in}
  482 commands.  Depending on the complexity of the model, the solids may be
  483 created in the desired location or created at the origin and later
  484 translated to the desired location.  Creation at the origin provides
  485 an opportunity to take advantage of possible symmetries in the geometry.
  486 Once all the solids are finished it is time to create the region[s],
  487 which will describe (to MGED) how to combine the solids to represent
  488 the model.
  489 
  490 The region[s] are then given the desired item/air code (if this is
  491 necessary, otherwise leave it as the system default value), and material
  492 codes.  The regions are then put onto a group, usually for functionality only.
  493 A group has no operations as such (like union [u], intersection [+] or
  494 difference [-]) and is just a collection of objects for convenient naming
  495 of a whole screen or collection of objects.