USE
- Last UpdatedJan 05, 2024
- 6 minute read
Purpose
To select/show parameters to control the following system facilities:
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Curves to be interpolated
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Fitting of Waterline Endings
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Section curves numbering convention
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(Un) Equal scaling of graphics
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Fitting of Decks
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Curve Endings
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Single Input/Output data file
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Normalised SAC representation
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Curvature representation
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Graphics Output device
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Loftbook Generation
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Tablet based menu
Syntax
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USE ( /SHOW ) |
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... |
Description
USE /SHOW
Lists the current settings of all the USE parameters.
USE CAMBER or SHEER
The named Camber or Sheer is made current and will be used in the creation of any subsequent Deck frames.
Examples
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USE CAMBER cammdk |
USE CD, FRAME or STATION
Selects the numbering convention to be used in specifying an x-value. Any x-value can be entered in terms of Constant Dimension (CD), a Frame number or a Station number. The CD number represents the true value on the x-axis, the Frame number is defined by a user input Frame Table (see CREATE FRAME command) and the Station number represents a user defined constant spacing (see the DEFINE AXIS command).
Examples
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USE CD |
USE DATA FILE
This option allows the use of partitioned input and output files that means, all input data to be contained in one file and all output data to be written to another. The format of a partitioned data file is as follows:
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*FILE* filename_1 |
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.Data for filename_1 |
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*EOF* |
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*FILE* filename_2 |
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Data for filename_2 |
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*EOF* |
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*FILE* filename_n |
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*EOF* |
The user may revert to separate data files by using the /OFF option.
The /SHOW option will show the user if the single data files are switched on or off and also the names of the files contained within the single input data file, if one is switched on.
Examples
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USE DATAFILE /INPUT /FILE= mydata.In |
USE DESIGN, SECTION, WATERLINE, BUTTOCK or DIAGONAL
When performing a GET or FIT command the system either obtains point data from the DESIGN directory ( Sections only ), or by interpolating stored curves. This command is used to select the source of the required data.
The following table illustrates which data can be used to create these curves:
Design |
Sections |
Waterlines |
Buttocks |
Diagonals |
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Sections |
YES |
YES |
YES |
YES |
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Waterlines |
NO |
YES |
YES |
YES |
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Buttocks |
NO |
YES |
YES |
YES |
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Diagonals |
NO |
YES |
YES |
YES |
Table 6: 2. The table Illustrates which data can be used to create these curves.
If a range or series of values is given for sections, waterlines or buttocks, then these values will be used when generating a loftbook from the surface.
Examples
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USE SEC |
USE FOS, FOB and PMB
When obtaining points for orthogonal curves using either the GET or FIT commands the system can be set to omit or include points within the Flat of Bottom (FOB), Flat of side (FOS) and Parallel Midbody (PMB) regions.
When set to OFF, which is the DEFAULT state, orthogonal curves within these regions are NOT interpolated but two Tangent points are inserted relating to the entry into and exit from the FOB and FOS areas
In order for this option to function correctly the FOB and FOS areas should be defined as closed curves that means, the curve being interpolated should cross the FOB or FOS curve twice. If the system cannot determine the flat area then all points will be included.
Examples
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USE FOB /ON |
USE GUNWHALE < /CONSTANT > Radius < fade-in-x > Aft-x Fwd-x < fade-out-x > < /VARYING >
This option is used when creating Decks and defines the Gunwhale or turns it ON or OFF.
A Gunwhale is defined by specifying its Radius followed by two to four values which define the longitudinal extent of the Gunwhale.
If only TWO longitudinal vales are given then the Gunwhale will be parallel between these two values.
If THREE values are given then these are taken to be a fade-in to a parallel section.
If FOUR values are given the Gunwhale is created as a fade-in, parallel and fade-out section.
In addition when using a fading Gunwhale the user may opt to have a CONSTANT ( the DEFAULT ) or VARYING radius over the fading regions by specifying the appropriate keyword.
Examples
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USE GUNWHALE 0.5 60.0 70.0 |
USE HALFSIDING, ELLIPSE, CIRCLE or ENDSURFACE
These options select the type of waterline endings and frame feet required at the Stem and Stern profiles.
Examples
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USE HALF |
USE NORMALISE_SAC
This option indicates that the system should use normalised area values for the SAC. If this option is used then the maximum sectional area becomes 1.0.
USE MANUAL or PRESELECTED
When fitting a curve to a set of data points the user has the option to select the Knot positions (defined using the MANUAL command) or let the system automatically assign the Knot positions (PRESELECTED). This option selects which method to use.
USE SCALE
This option indicates that the system should use differential scaling for the U and V axes so that views will fill the entire graphics area. Normally the U and V scales are both the same.
Examples
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USE SCALE |
USE TUFT < $N >
By default when the Curvature is displayed it is drawn as a continuous curve which follows the curve. When the USE TUFT command is used the curvature is drawn as vectors normal to the curve. The length of the vector indicates the magnitude of the curvature at that point. The number of TUFT vectors per span can be altered by supplying a number. See also MAGNITUDE command.
USE *LOFTBOOK
This option indicates that a loftbook is to be created with the given name. Subsequent CROSS and DIRECTORY command will be output to the loftbook. The loftbook is closed by issuing the USE *SCREEN command. The additional qualifier /MODE allows the user to select 80 or 132 column output or comma delimited (CSV) output. The number of rows and columns per page can be altered by specifying the /ROWS and /COLUMNS qualifiers.
If the /SURFACE qualifier is given, then the loftbook is created from the surface patches instead of curves. If the /TOL qualifier is given, then offset table data for 3D curves is checked and the user is warned if the data is further away from the surface than the given tolerance.
Examples
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USE *LOFT LOFTBOOK.LIS |
USE *PLOTTER
This option indicates that a plot file is to be created with the given name. All subsequent graphical operations will cause plot instructions to be written to the plot file. The plot file is closed by issuing the USE *SCREEN command.
The plot file is a simple sequential text file. Each line of file contains one of the following commands starting in the first column:.
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Command |
Description |
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P |
n |
Select pen number n |
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L |
n |
Select line style n |
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M |
x |
y |
Move to absolute (x,y) |
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D |
x |
y |
Draw to absolute (x,y) |
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C Message |
Comment |
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F |
Finish Plot |
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1 |
14 Col No |
26 |
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Table 6: 3. The plot file commands.
The additional qualifier /SURFACE indicates that the sections, waterline and buttocks will be drawn from the surface, rather than from the curves.
Examples
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USE *PLOT lines.plt |
USE *SCREEN
This option is used to close the Loftbook and Plotfile thus returning to normal interactive graphic manipulation.
USE *TABLET and *VDU
These options swap between keyboard and bitpad menu operation.