Monday, 12 October 2015

Powerful Ship Hull Design in Rhino with Rapid Hull Modeling Methodology




This is a powerful way to design and generate any vessel hull in Rhino3d, by creating a few master curves which describe the stem, stern, mainframe etc. This methodology is applicable to ships, yachts, boats, workboats and multi hulls.
As the input curves are the DNA of the resulting shape, you can exchanges curves for other curves to make variations of the shape. This is a very important feature to manage your hull design well. Furthermore it is always possible to fair the hull surface later with direct control point manipulation.


Advantages:
  • Easy to the edit shape and size later (especially with ‘record history’ in Rhino 4) 
  • Systematic variations possible by exchanging input curves
  • Fair single surface hull 
  • Fast generation of new concepts 
  • High quality bulbous bow and parallel midship section 
  • Free
  • Posibility to parametrize the design with scripts
    Disadvantages:
    • Singularities are possible when two or more control points of the surface are at the same position
    • More difficult to use than Orca3d for sailboat, planing hull and ship without bulbous bow


      Grasshopper Parametric Ship Hull Modeling




      Parametric hull modeling for concept design, requires a flexible and versatile approach. Rhino enables this in combination with Grasshopper scripting.
      Another new application is to create a systematic variation of a ship hull for CFD calculations to find the design with a minimum resistance.

      We are proud to publish two ways to model and design ship hulls with free open source Grasshopper scripts. The two scripts that are published enable you to model a bulbous bow and pram aft body type hull with a press of a button. Both solutions are based on our Rapid Hull Modeling Methodology which is the manual way to design a ship hull in Rhino.

      The first solution (01 RapidHullFullyParametric.GH) is only a script which contains a fully parameterized hull in which also the loft curves are scripted. This is a more academic script that optimizes the design of one type of ship hull. For this you only have to open a new Rhino session and then activate the script. For modeling other ship types you have to fully understand the hull definition in the script and this is not so easy.

      The second solution is a combination of a Rhino file (02 RapidHullPartlyParametric) that contains the loft curves as well as a script (02 RapidHullPartlyParametric) that contains the rest of the solution. The idea here is that the physical Rhino loft curves are input for the lofting in the script. The advantage of this script is that you can create easily new ship type solutions by modifying or even replacing the loft curves. In the Rhino file you'll find several ship types.

      Downloads:
      The first script is the result of a collaboration of the following people from their respective companies and organisations:
      • Bas Goris, GustoMSC, started the quest for Rhino hull modeling methods
      • Phil Shapiro, Cadlantique, presented the loose loft 3d curve technique
      • Bart van Oers, TU Delft, put this Rapid Hull Modeling methodology in Rhino Script
      • Julien le Rouzic, GustoMSC, converted the Rhino Script into a Grasshopper Script
      • Gerard Petersen, RhinoCentre, added real time lines plan and displacement functionality

      For us it is important that you share your experiences, changes and additions to the script. So please send them to us and we can learn from you!






      Tuesday, 6 October 2015

      Lapstrake boat hull in Rhino with Grasshopper




      Model and design lapstrake boat hulls like this viking ship with Rhino and Grasshopper scripts.
      Modeling lapstrake hulls in 3D is actually quite challenging. When they are modeled by hand, it is very time consuming to edit the shape at a later time. In order to create more flexibility, a Grasshopper script makes it possible to easily edit the shape and also instantly see some hydrostatics and a linesplan.

      Try out yourself by downloading the zip file which contains a Rhino file as well as three different scripts:
      1. lapstrake-no overlap is the script of the video. Strakes do not overlap.
      2. lapstrake-no overlap-GRP is a script that creates a hull with a smooth inner skin.
      3. lapstrake-overlap is a script that actually creates strakes that overlap. However this doesn't result in perfect solutions.





      Demonstration movie of modeling lapstrake hulls with Grasshopper






      Drawing of a Viking ship that is used as reference