Converting GHS models to DAVE

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Converting GHS models to DAVE#

Geometry#

The geometry of a GHS model can be saved as a .gf1 file. Such a file contains the definition of the hull and tanks. PyMeshUp contains methods to read these geometry files.

The DAVE-vessels module has a function GHS_to_DAVE to build a DAVE .vessel file from the data in the .gf1 file.

This includes:

  • Tanks and tank geometry

  • Hull shape

Frames with a radius can be discretized using a user-defined angular step (default 10 degrees)

image-20230816131422758

The meshes are simplified as much as possible without modifying the geometry. This mainly means removal or duplicate or redundant frames. The resulting shapes are efficient for use in DAVE or as basis for a panel model for diffraction analysis.

image-20230816131555170

All uses shapes are saved as .stl files and can be used as basis for a visual.

The produced .vessel file works but needs some manuals additions. These are listed in the header of the produced file as a todo-list:

#    THIS FILE IS AUTOMATICALLY EXPORTED FROM THE GHS (GF1) GEO FILE.
#    MAKE A COPY OF THIS FILE AND EDIT THE COPY.
#    
#    IN THE COPY:
#    [ ] ADD A HEADER WITH A DESCRIPTION OF THE VESSEL AND THE SOURCE OF THE DATA
#    [ ] ADD LIGHTSHIP WEIGHT

#    
#    OPTIONALLY
#    [ ] CHANGE THE VISUAL, IT IS INITIALLY SET TO THE HULL BUOYANCY PARTS (WHICH IS OK) BUT YOU PROBABLY WANT SOMETHING ELSE
#    [ ] ADD ADDITIONAL (NON BALLAST) TANKS IF ANY
#    [ ] ADD INERTIA IF YOU WANT TO DO DYNAMICS, AS GUIDANCE:
#        rxx = 0.3..0.4 * WIDTH
#        ryy = rzz = 0.22 ... 0.28 * LENGTH
#    [ ] ADD BOLLARDS IF ANY
#    [ ] ADJUST THE DRAFT MEASUREMENT POINTS IF NEEDED
#      
# REVISION HISTORY
# rev   |   date 		|   description
# 0	| 2023-08-16 11:19	|   auto-generated from: filename.GF1

General properties of the barge (length, width) are extracted from the geometry and are used to fill the barge length and cut-planes.

The hull-shape is set as visual by default.

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