
 SET, Introduction
 
 The SET  commands are  used to  set   various   parameters which
 affect   other   commands,  and  operations in QikDraw 3D. These
 parameters include:
 
   -   Screen depth  which defines  the default  distance in,  or
       out of   the   screen at which points added using the puck
       will be placed.
   -   Setting tolerances  which define  how accurately  elements
       must be  located,  the  maximum  distance  a  point can be
       from a  plane, and  still be  considered on the plane  and
       how   close lines  must  be  before  they  intersect,  and
       defining the  accuracy to  which circles  and arcs will be
       drawn.
   -   Defining the x and y spacings of QD3D's reference grid.
   -   System  re-initialization  (all  parameters    reset    to
       default values, any current model information is lost).
 
 On  first   entering  QikDraw,   all  SET  parameters  are  pre-
 initialized (ie.  assigned default  values), so that drawing may
 proceed   without the need to explicitly "SET" these parameters.
 Subsequently, SET  commands may be used while creating a part to
 change individual parameter values to suit current requirements.
 
 
 "SET DEPTH"
 
 This command  is used  to specify  the default  depth  that  new
 points  will be given when added using the puck. Positive values
 of the  depth will  add the  points in  front of the screen, and
 negative   values of the depth will add points behind the screen
 front plane. The default depth is used by all commands which add
 new  points, eg. POINT ADD, LINE ADD, CIRCLE ADD, PLANE ADD etc.
 
 When QD3D  is initialized,  the default  depth is  0., and,  the
 plane that  is coplanar  with the  screen is the x-y plane, with
 the z-axis  pointing out  of the  screen. When  points are added
 using the  PUCK, then they are added in the x-y plane and with z
 coordinates of  0. This is because the depth is set at 0. If the
 depth was set at -10, then all PUCK point additions would have z
 coordinates of -10.
 
 Procedure
 .   Enter the default depth.
 
 
 "SET MODE"
 
 Mode commands  determine whether or not to use the grid, to ring
 the bell  and to  activate the  construction plane.  The options
 appear in a tertiary menu and can be toggled on/off.
 
 SNAP (NO SNAP)
 
 This command  draws the  default  grid  definition  (or  a  grid
 defined using  SET GRID)  on the  screen.   Whenever a  point is
 added on  the screen  using the  puck, the location of the point
 will be  the nearest  grid point  to the  puck.   If the user is
 snapping  to  an  already  existing  point  then  Snap  mode  is
 overridden.
 No Snap   turns  off the  grid set  up by Snap.  Points added no
 longer snap to grid locations but are added as normal.
 
 QUIET (NO QUIET)
 
 This command  turns off  the bell;  it is  not  rung,  even  for
 errors.   No Quiet   turns  the bell on and it is rung with each
 user prompt.
 
 CON PL (NO CONPL)
 
 This activates  the user's  construction plane.    Points  added
 using the  central  puck  button  will  be  projected  onto  the
 construction plane.   Axes  showing the orientation of the plane
 is displayed in the top left-hand corner of the screen.
 NO CONPL deactivates the contruction plane.
 
 
 "SET TOLR"
 
 This command  defines four  tolerances. The  first  is  a  plane
 tolerance. This  tolerance specifies how far away from a plane a
 point may  be, before  it is no longer considered to be lying on
 the plane. The line tolerance specifies how close two lines must
 be to  be  considered  as  intersecting.  The  circle  tolerance
 specifies   how accurately  circles and  arcs are  drawn on  the
 screen. The  snap tolerance  specifies how  accurately  circles,
 lines and  points   must be  identified to  be found.  The  snap
 tolerance also defines  the size of the cross, used to represent
 the points.
 
 In QD3D,  circles/arcs are  drawn as a sequence of straight line
 segments, although  in most  cases this  is not  apparent to the
 user, provided  the number  of sides  defined for  the entity is
 sufficiently large  in proportion  to it's  on screen  size. The
 resolution applied  to the  drawing of  circles,  cylinders  and
 revolved arcs  may be  defined by  the user  to improve  the  on
 screen drawing  speed. Changes  to the values are allowed in the
 range [0.001,0.25].  This resolution  can be  set in  the  third
 prompt of this command.
 
 Procedure
 .   Enter plane tolerence.
 .   Enter line tolerence.
 .   Enter circle display resolution.
 .   Enter snap tolerence (for grid).
 
 
 "SET *CONP"
 
 The  SET  *CONP  commands  allow  a  construction  plane  to  be
 specified.   It can  be activated  and deactivated  with the SET
 MODE command.  Once activated the points added using the central
 button will be projected onto the construction plane.
 
 If SET  *CONP is  selected with the central button then the user
 will be prompted to enter four points.  The first pair of points
 define a  horizontal vector  in the  construction plane (its "x-
 axis") and  the second  pair define  a vertical  vector  in  the
 construction plane (its "y-axis").
 
 If the  command is  selected with  the left button then the user
 must locate  an existing  plane in  the model;  the user is then
 prompted to  choose between  two normals  for the z-axis (of the
 construction plane).
 
 

 "SET GRID"
 
 This command  is used  to specify the grid spacing. In QD3D  the
 grid is  based on  the current view. Points added using the puck
 will snap  to the nearest displayed grid point, and will  have a
 depth given  by the  default depth.  A reference  grid point  is
 displayed every  n (n  user defined)  grid units as specified by
 this command.
 
 Upon initializing to QD3D, the grid spacings are as follows:
 
 Horizontal           50
 Vertical             50
 Reference point      10
 
 The reference  point refers  to how often a reference grid point
 is draw.  A reference  point does  not have to be drawn at every
 grid point but rather every second, third etc. if so desired.
 
 Procedure
 .   Enter horizontal grid spacing.
 .   Enter vertical grid spacing.
 .   Enter reference point spacing.
 
 
 "SET *COLR"
 
 In QD3D,  there is  a colour  table with 256 locations (numbered
 from  0   to  255)   each  of  which  contains  a  specific  RGB
 combination. This  command is  used to  set one or more of these
 locations to  a user  specified colour.  These are  all  set  by
 defaults when the user enters QikDraw, but these defaults can be
 changed. A  colour table  location is selected from the tertiary
 menu and then this location is defined as any combination of the
 three colours red, green and blue. The format for the definition
 is as follows:
 
 009900        specifies 0% red, 99%green, 0% blue, giving green.
 670067        specifies  67%  red,  0%green,  67%  blue,  giving
 purple.
 
 If the  user has some line drawn in colour 1, and he/she changes
 the colour combination definition in box 1, then those lines are
 immediately changed to reflect the new definition.
 
 Procedure
 .   Enter the location number to change.
 .   Specify the RGB combination for that location.
 
 
 "SET COLR"
 
 This command is used to set the default colour to be used in all
 entity additions.  The desired  location in  the colour table is
 selected and  the colour  defined in  that location used for any
 future entity  additions or  changes.   There are  256  possible
 colours in QD3D.
 
 Procedure
 .   Enter the number of the colour table location to use.
 
 
 "SET LAYR"

   
 This command  is used  to define  which layer the user currently
 wishes to work on. A part can consist of many entities and these
 entities can  be drawn  in different  layers. This  is a  way to
 unclutter a  complex drawing. Entities can be drawn in different
 layers and  these different  layers need not all be displayed at
 the same time.
 
 Any entities  added from  this command  onwards, are drawn in at
 the specified  layer. There  are up  to 256  layers  in  QikDraw
 numbered from 0 to 255.
 
 Procedure
 .   Enter default layer to draw entities in.
 
 
 "SET *LAYR"
 
 This command  is used  to specify  which layers of a drawing are
 currently active,  ie. are  to be  displayed on  the screen. The
 command acts  as a toggle switch. First you are asked which part
 of the  layer table  to display  on the  screen (the whole table
 cannot fit  into tertiary menu so the table must be displayed 64
 at a  time). If the selection button is pressed while located in
 a layer  box, if  that layer is currently active, it is rendered
 inactive and  visa versa.  The screen  is immediately updated to
 reflect the new layer definitions.
 
 Procedure
 .   Enter the base of the table to display in tertiary menu.
 .   Select any layer from tertiary menu to change.
 .   Press the termination button to finish.
 
 
 "SET CLEAR"
 
 This command  is  used  to  re-initialize  QikDraw  3D.  QikDraw
 parameters are  returned to their default values and any current
 part information  is lost  and is not recoverable in the current
 session. If,  having executed  this command,  the user  realizes
 that   the information  lost was  in fact  needed, then  at this
 point (or  at a  later time)  the  user  can  recover  the  lost
 information by  quitting QikDraw and replaying the session up to
 the point  where   the SET  CLEAR  command  was  executed,  then
 terminating the  replay  at this point. For details on replaying
 QD3D sessions, see 1.3 CONTROLLED REPLAY OF PREVIOUS SESSIONS.
 
 After  executing  this  command,  the  screen  is  cleared,  all
 drafting information  is lost  (note that  the  STATISTICS  AREA
 values  are  reset  to  zero)  and  QD3D  parameter  values  are
 reinitialized (ie. returned to their default values).


