COMPARING DATA

The Compare Data menu item opens the Compare Data form, which allows you to find differences between the data in two OrcaFlex files.

The comparison is done using a user-provided compare program, so when you first use this facility you need to configure OrcaFlex to tell it which compare program that you want to use; see Configuration below.

You can then compare files as follows:

 On the Files page, specify the two files that you wish to compare. These can be data or simulation files.

 Click the Compare button.

 OrcaFlex then saves the data from the two files to temporary text files and then runs the user-specified compare program to compare those text files.

As an alternative to comparing two data files on disk you can optionally choose to compare the currently loaded model with a single file on disk.

Configuration

On the Configuration page you need to tell OrcaFlex the text file compare program that you want to use, and how to use it. The compare program must be a program that can compare text files passed to it through the command line.

Many such programs are available on the web; we at Orcina have a preference for WinMerge.

User Interface, Preferences

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Compare Program

This is the compare program's executable file name. You can specify either the full path, or just the file name if the executable file resides in a directory which is on your system path.

If no program is specified OrcaFlex uses a very basic, built-in, compare facility.

Command Line Parameters

This defines the command line parameters that are passed to the compare program. OrcaFlex replaces the special strings %1 and %2 with the file names of the temporary text files.

OrcaFlex also replaces special strings %name1 and %name2 with readable names describing the two files or objects that are being compared. Not all compare programs have the capability of assigning readable names and just use the file name, so the use of this facility is optional.

For most compare programs the default setting of %1 %2 will be sufficient. Otherwise you will need to consult the documentation of your compare program.

If you are using WinMerge then we recommend using the following: /e /x /s /dl %name1 /dr %name2 %1 %2

3.15 PREFERENCES

OrcaFlex has a number of settings that can be customised to suit the way that you work. The majority of settings can be adjusted in the Preferences form, which is accessed by using the Tools | Preferences menu item.

3D View

Minimum Mouse Drag Distance

Object positions are not updated until the mouse has been dragged at least this distance (in pixels). This prevents accidental changes to object positions. To make a small movement, drag away and then back again, or edit the coordinate directly in the object's Edit Form.

View Rotation Increment

Each CLICK on a Rotate View button increments or decrements View Azimuth or Elevation by this amount.

Refresh Interval

During a calculation all 3D View and Graph windows are updated at the rate specified. Different refresh intervals can be used for static and dynamic calculations.

Wire Frame Drawing Timeout

This sets the maximum amount of time that OrcaFlex will allow for the drawing of the sea surface in wire frame 3D views. If the drawing procedure exceeds the permitted time then the sea surface will not be displayed. This limit will commonly only affect models with a high sea surface grid density and/or number of wave components. 3D views with a Disturbance Vessel may be more prone to timing out due to the extra computational effort required to calculate the shape of the disturbed sea surface. A value of zero means that OrcaFlex will never timeout the wire frame drawing.

Background Colour

This sets the background colour of all 3D View windows.

Locate Object Method

Can be either Flash object or Hide other objects. It determines what method the Locate action in the model browser uses.

 When the Flash object preference is set then the Locate action repeatedly draws and hides the object on the 3D View, like a blinking cursor.

 When the Hide other objects preference is set then the Locate action temporarily hides all other objects.

Normally the default setting of Flash object is sufficient to locate objects. However, if the model you are searching for is obscured by other objects then this method may not help you to locate the object. In this case you should use the Hide other objects preference.

3D View Axes View Axes

The view axes show the same directions as the global axes, but are drawn in the top right-hand corner of 3D views, rather than at the global origin. Can also be set from the View menu.

Scale Bar

Determines whether a scale bar is drawn in 3D views. Can also be set from the View menu.

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User Interface, Preferences Note: The Scale Bar is not drawn for shaded graphics views because it would be meaningless due to

perspective.

Global Axes

Determines whether the global axes are drawn, at the model's global origin (0,0,0). Can also be set from the View menu.

Environment Axes

Determines whether the wave, current and wind directions are drawn in the 3D view. When multiple wave trains are present the first wave train is taken to be the dominant one and is drawn using sea surface pen, whereas the other wave trains' directions are drawn in the secondary wave direction pen. Can also be set from the View menu.

Local Axes

Determines whether the local axes for vessels, buoys and line ends are shown. Drawing the local axes on the 3D view helps you check the orientations of these objects. This preference can also be set from the View menu.

Note: Local Axes are not drawn for shaded graphics views.

Node Axes

Determines whether axes for line nodes are shown. This preference can also be set from the View menu.

Out of Balance Forces

If selected, then in the static analysis (not during the simulation) there are extra lines drawn on the 3D view, representing the out of balance force acting on each vessel and buoy. This preference is sometimes useful for static analysis, since it enables you to see how far a buoy or vessel is from being in equilibrium. This preference can also be set from the View menu.

The force is drawn as a line, starting at the force's effective point of application, and whose length represents the size of the force. The scaling is piecewise linear and based on the View Size of the 3D view. Lines up to ViewSize/2 long mean forces up to 10 force units and lines from ViewSize/2 to ViewSize mean forces from 10 to 1000 force units.

Note: Out of Balance Forces are not drawn for shaded graphics views.

Video

The video preferences allow you to control the compression algorithm used for exported video. The software which performs this compression is called a codec. Because the different graphics modes produce very different images they require different types of codec.

Shaded Graphics Codec

The run-length encoding which works well for wire frame graphics is not suitable for shaded replays and in fact there is no suitable built-in codec in Windows. We would recommend using an MPEG-4 codec of which many are available. In our experience the freely available (licensed under the GPL) XVID codec performs very well. The Shaded Graphics topic has more information about the XVID codec.

You can choose to use other codecs that are installed on your machine. Should you do so then you must also specify the following information:

 Codec 4 character code: Codecs are identified by unique codes, 4 characters long. Good alternatives to XVID include DIVX, the 3ivx codec (character code 3IV2).

 Padding: MPEG-4 codecs commonly require round number frame sizes (width and height in pixels). For example XVID requires frame sizes to be multiples of 8. When OrcaFlex exports the video it ensures that the frame sizes are a multiple of this number. If you are unsure of what number to use for your codec then we recommend trying 8 which usually works.

 Colour depth: Some MPEG-4 codecs require a specific colour depth. Again, if you are unsure of what value to use then we recommend trying 32 bit or 16 bit colour depth.

Wire Frame Graphics Codec

Run-length encoding is the default setting and is usually the best choice. This codec offers good compression rates for OrcaFlex wire frame video. The AVI files produced using this codec can be played on most Windows PCs.

If you choose Uncompressed then each frame of the video is stored as an uncompressed bitmap. This means that the AVI file produced can be extremely large.

User Interface, Preferences

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Output

JPEG Compression Quality

A value between 0 and 100 that determines the quality of exported JPEG files. Lower values have worse visual quality, but greater compression (i.e. smaller file size). Higher values have better visual quality, but less compression (i.e. larger file size).

Add program/file details to output

If this is checked then external output includes text with details of the program version, file name, file modified time etc.

Default File Types

OrcaFlex outputs files of a wide variety of formats. For example, spreadsheets can be output in Excel, comma separated or tab delimited formats. When you save a file, you can select which format to use with the Save as type drop-down on the standard file dialog. The default file types preferences allow you to control which file format is first selected when a file dialog opens.

Messages

A number of OrcaFlex warning messages can be disabled by checking Don't show this message again on the warning message form. Once a message has been disabled, it will not be shown again. These messages can be re-enabled by checking the appropriate box on this page.

Miscellaneous Show Splash Screen

Determines whether OrcaFlex displays its splash screen when the program starts.

Batch Auto Save

If this is enabled then simulations run in batch mode are automatically stored to simulation files at the specified regular Auto Save Interval. This is useful if your computer is prone to failure (for example because of overnight power failures) since the part-run simulation file can be loaded and continued, rather than having to re-run the whole simulation from scratch. The Auto Save Interval should be neither too short, since then the program will then waste a lot of time repeatedly storing away the results, nor too long, since then a lot of simulation work will be lost if a failure occurs.

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Automation, Introduction

4 AUTOMATION

4.1 INTRODUCTION

OrcaFlex provides several important facilities for automating and post-processing work:

 OrcaFlex is supplied with a special Excel spreadsheet which enables you to automate the extraction of simulation results into your own spreadsheet. You can then use the normal Excel calculation facilities to do your own customised post-processing and graphing.

 The Batch Processing facility enables you to run a set of simulations in unattended mode, for example as an overnight job. The simulations can either be of pre-prepared data files, or else can be specified by a batch script file that specifies the simulation as variations on a base data file. The OrcaFlex Spreadsheet mentioned above also has facilities for automating the production of batch script files and text data files. Models can define post calculation actions which are executed after batch analyses.

 OrcaFlex includes a well-documented programming interface called OrcFxAPI (short for OrcaFlex Application Program Interface). See the OrcFxAPI help file for details. OrcFxAPI is a Windows dynamic link library (DLL) that is installed when you install OrcaFlex, and which provides facilities for setting data, calculating static positions and extracting results from those calculations or from pre-run simulation files. For example you can write programs to automate post-processing or that use OrcaFlex as a statics calculation engine. One important example application of this is for real-time monitoring of pipes, moorings etc. For further information or to discuss possible applications of OrcFxAPI, please contact Orcina.

4.2 BATCH PROCESSING

In document OrcaFlex Tutorial (Page 79-83)