------ Command; interactive; group 6 -- -
VIEW....command used to display and modify cartesian, cylindrical- polar and body-fitted grids in a plane-by-plane fashion.
VIEW has two formats; the first one (with parameters) is used to display a plane on the screen. The second one (without parameters) is used to access an interactive environment called the "VIEW sub- system". When VIEW is used with arguments, it has the format VIEW(plane,index). For example, VIEW(I,5) projects on to the VDU screen the YC and ZC coordinates of the surface of constant I. The VIEW command used without arguments enters the VIEW sub-system.
For further information, see the PHOENICS ENCYCLOPAEDIA entry for VIEW
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VI[ew] <direction>....sets the view direction, which is the conceptual line, perpendicular to the display surface, along which the plot is viewed.
It may be specified either as an axis direction (e.g. VIEW Z), or by treating the three direction cosines to specify an arbitrary 3D line (e.g. VIEW 1 1 1 defines the commonly used 3D viewpoint at 45 degrees to all 3 axes).
A combination of the VIEW and UP directions specifies the orientation of the plot. NOTE that these two directions cannot coincide, by definition.
See also : UP
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[View] activates the sub-menu for viewing control including rotating, magnification and so on.
(see Group 6)
VIEW....command used to display and modify cartesian, cylindrical- polar and body-fitted grids in a plane-by-plane fashion.
VIEW has two formats; the first one (with parameters) is used to display a plane on the screen. The second one (without parameters) is used to access an interactive environment called the "VIEW sub- system". When VIEW is used with arguments, it has the format VIEW(plane,index). For example, VIEW(I,5) projects on to the VDU screen the YC and ZC coordinates of the surface of constant I. The VIEW command used without arguments enters the VIEW sub-system.
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Use mouse or cursor key to move cursor to a button and click or press RETURN once to select. Or use comma ',' and dot '.' to jump the cursor over buttons and press space bar to select.
New Points
Use mouse to create new points in the black window. To quit from this mode, move cursor out of the black window and click once. If the cursor is on a button, the button is also picked.
Double clicking on this option will allow users to type in coordinates for new points in a tabular from.
New Straight Lines
Select two points by moving cursor near the first point and clicking then moving cursor near the second point and clicking. As soon as the two points have been selected, a new line with one cell in it is created.
It is not permitted to create a new line to join two points which have already been used as the starting and ending points of another line.
To quit from this mode, move cursor out of the black window and click once. If the cursor is on a button, the button is also picked.
New Arc Lines
Select three points in the order: starting point, middle point and ending point. An arc line with one cell in it is created.
New Curve Lines
Select a number of points to generate curve line. Leave up to two points for setting boundary conditions. When all the points on the curve (not the points for boundary conditions) have been selected, move cursor out of the window and click once.
If no boundary condition is required, keep the cursor out and click again.
If at least one boundary condition is to be set, move cursor back in the window.
To set boundary condition at starting point, select another point. The direction and length from the starting point to the selected point will decide the starting boundary condition. If no condition is required, select the starting point.
To set boundary condition at ending point, select another point. The direction and length from the selected point to the ending point will decide the ending boundary condition. If no condition is required, select the ending point.
A new curve line is created.
To quit from this mode, move cursor out of the black window and click once. If the cursor is on a button, the button is also picked.
You have to complete the curve line before quitting.
New Frames
Start from one corner point, select all the line-connecting points (not points used inside
arc and curve lines) until reaching the starting point again. The starting point will
automatically become the first corner point. You still need to select the remaining three
corner points unless they can be decided by what are available.
If numbers of cells at the frame boundaries do not match, the frame name is displayed with at least one negative number; otherwise, the correct number of cells in each direction is displayed.
Move Points
Select the point you want to move. Move cursor to a new place and click once. The selected
point is moved to the new place.
To quit from this mode, move cursor out of the black window and click once. If the cursor is on a button, the button is also picked.
Double clicking on this option will allow users to type in coordinates for moving points.
Cells
Used to modify number of cells on lines. Select a line by moving cursor near the name of
the line and click once. A data input box appears with the current number of cells. Change
it by typing in the correct number and press RETURN.
To quit from this mode, move cursor out of the black window and click once. If the cursor is on a button, the button is also picked.
Powers
Used to modify the cell distribution on lines. The powers can also be backwards '-pwr' or
symmetrical 'Spwr'. Operation similar to 'Cells'.
Dimension
Used to set grid dimension and default grid size. You must do this before matching the
grid.
Match Grid
Once this option is selected, you need to pick a frame for matching. When a frame is
picked, you can see a panel of various parameters. Make changes and select 'OK'.
To unmatch a frame, set corner index to 0.
One option in the match panel is 'Grid check'. You can select it to switch on or off the grid orthogonality checking on the matched grid.
OK
Write PIL commands in COPYQ1 and exit.
Normal
Normalize the scale to fill the picture in the black window.
Reduce
Reduce the scale of the picture. You need to move cursor into the window and click at two
positions. The whole picture will be reduced to that size.
Magnify
Enlarge the scale of the picture. You need to move cursor into the window and click at two
positions. Picture within that area will be enlarged to fill the whole screen.
Z=0.000E+00
This button controls the third location of the current working plane. It can be directly
changed by activating this button and typing the new number.
High Value
It shows the coordinate of the high boundary and controls the scale in the vertical
direction
Vertical Direction
It shows and changes the vertical direction
Low Value
It shows the coordinate of the low boundary and controls the offset in the vertical
direction
Left Value
It shows the coordinate of the left boundary and controls the offset in the horizontal
direction
Horizontal Direction
It shows and changes the horizontal direction
Right Value
It shows the coordinate of the right boundary and controls the scale in the horizontal
direction.
The VIEW sub-system provides a full-screen,menu-driven, graphic environment through which the user can view and MODIFY the grid.
When the command VIEW is issued, a full-screen graphic display will appear on the VDU, with a menu panel on the right-hand-side of the screen, providing the following options and information:
DIMENSION
The number of cells in each coordinate direction is displayed under this heading, in the
form (NX,NY,NZ)
GRID TYPE
The current grid type is displayed under this heading. To change the grid type, position
the cursor in the highlighted box labelled 'GT' and click the mouse or press return, enter
1, 2 or 3 for the required grid type and press return.
PLANE AND NUMBER
The current grid plane and number are displayed under this heading. To draw a different
grid plane on the screen, select 'PL', then either 'I', 'J' or 'K', then enter the plane
number and press return. To clear the graphic display, select 'PL', then position the
cursor to the left of the 'I' box and click the mouse or press return.
VIEW DIRECTION
The current view direction is displayed under this heading. To change the view direction,
select 'VD' and then select one of the six options: +X, -X, +Y, -Y, +Z or -Z.
Alternatively, for a perspective view, move the cursor outside the view options box and
click the mouse (or press return). The prompt 'V-DIR->' will appear: enter the three
components of the view vector (separated by commas) and press return. After the view
directionhas been changed, only the last grid plane will be displayed.
UP DIRECTION
The up direction can be changed in the same way as the view direction, except that only
one of +X, -X, +Y, -Y, +Z or -Z can be chosen.
PRINT COORDINATE
This option permits display of corner coordinate data for cells on the current grid plane.
Select 'PC', then position the cursor at any grid node for which the coordinates are
required and click the left mouse button (or press return); both the cell number and the
Cartesian coordinates will be displayed at the top of the screen. To select a new point,
first click the middle mouse button (or type '?'), then move the cursor to the new point,
and click the left mouse button (or press return).
To move a grid node (BFC grids only), position the cursor at the grid node and click the left mouse button. Then move the cursor to the new position and click the left mouse button again. The new coordinates of the point will be displayed at the top of the screen
To finish, position the cursor in the 'PC' box and click the middle mouse button (or type '?').
BUILD GRID
Choose this option to modify the existing grid: a list of commands and the prompt- Command
?-> will appear on the left hand side of the screen.
The commands available are:
Init Grid initialization: for Cartesian or polar grids, this command sets the default grid of 1 cell in each direction. For BFC grids this command clears all points, lines and frames.
REDraw Redraw the current picture
USE <filename> Read commands from a file named <filename>.
END Quit the Build Grid option.
? List available commands.
Point pnam xp yp zp Define or modify a point
V arg1 arg2 arg3 Define a curve.
Line lnam pnm1 pnm2 nseg powr... Define or modify a line
Frame fnam p1 m1 p2 m2 p3 m3 p4 m4 Define or modify a frame
Dim nx ny nz dx dy dz Define the dimensions of a BFC grid
Match fnam direc i1 j1 k1 style Match a grid mesh on a frame.
Block i1 i2 j1 j2 k1 k2 style Set internal grid points for a 3D block
Copy pln2 F pln1 i1 i2 i3 i4... Copy a grid plane by means of shifting or rotating.
The above command strings are the arguments of the equivalent GSET commands (see GSET entry in Group 6)
| NREGi j | Set number of regions to j in i direction, where i is X, Y, Z or T. |
| IREGi j | Set the current region to j in i direction, where i is X, Y, Z or T. |
| i ni il pwr | Set GRDPWR(i,... in the current i region, where i is X, Y, Z or T, ni is the total number of cells in the i direction and il is the total extent of the grid. |
| SHOW ALL | Display the GRDPWR settings in all directions. |
| SHOW i | Display the GRDPWR settings in i direction, where i is X, Y, Z or T. |
RINNER y0 Set inner radius (see entry on RINNER in Group 4)
EXIT Select 'X' to return to the Satellite interactive mode.
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The X component of the view vector defined in physical space.
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The Y component of the view vector defined in physical space.
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The Z component of the view vector defined in physical space.
Because PHOTON represents three-dimensional objects on a two-dimensional screen, it is necessary to specify the direction from which the object plotted is to be viewed, and its orientation. To do this, you specify a 'view' direction, V, and an 'upright' direction, U.
The view-direction vector, V, is a vector of arbitrary magnitude that points from the view-point, at infinity, to the cartesian-coordinate origin. You specify the orientation of the projection on the screen by the upright-plane vector U which lies in a vertical plane perpendicular to the screen. You specify both vectors in terms of their resolutes along the cartesian axes X, Y and Z shown in the bottom right-hand corner of the VDU screen.
The U and V directions cannot be the same: the program issues an error message if an attempt is made to make them so.
You set the U and V directions by means of the commands UP and VIEW, the arguments of which specify the direction.
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The distance between the focus point and the view plane. Only effective if PerspVU has been switched on.
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