ModiYacht - Feature-line and Attributive based Shape Modifiers for External Design of Superyachts

Erkan Günpınar      Shahroz Khan      Kemal Mert Doğan     Salih Ertuğ Övür

Short Summary

A yacht is a recreational boat or ship whose external appearance should attract customers in order to make them buy it. Computer-Aided Design (CAD) softwares that are utilized for external design of these yachts are not easy to use and can be utilized by experienced design engineers. Improvements in design tools enable designers to generate innovative designs and increases their flexibility. User friendly design tools enables even customers to involve the design process to some extent.

This project involves three main research issues. First of all, a novel design framework for the generation of planing, displacement and semi displacement hull types has been proposed. The hull is divided into three regions: entrance, middle and run. Geometric parameters are defined on the hull and shape operators generates new hull types based on these parameters. The modifiers take three quality criteria into account: G1 geometric continuties between neighboring regions, hull fairness and independent modification of geometric parameters. Second research work is to learn hull adjectives (such as strong, speedy) defining hulls via surveys. Relationships between hull adjectives and geometric parameters are learned by means of machine learning algorithms. Finally, a novel model sampling algorithm has been proposed for the generation of adjective-based hull models. The sampling algorithm is based on teaching and learning based algorithm and generates desired number of adjective-based models automatically. 

The main outcome of this project is ModiYacht CAD tool that can generated hull variations. Via user interface of this software, parametric and adjective-based model variations can be obtained. The modified hull can be exported in standard file format so that hydrodynamic analyses can be performed.

The project was supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project Number: 214M333)


Journal Papers

1. Shahroz Khan, Erkan Günpınar, Kemal Mert Dogan, “A Novel Design Framework for Generation and Parametric Modification of Yacht Hull Surfaces”, Ocean Engineering, Vol. 136, 05/2017, s. 243–259.


This paper proposes a new design framework for the parametric design and shape modification of yacht hulls. In this framework, the hull is divided into three sections (entrance, middle and run) and each section is represented separately. In this way, a designer has better design flexibility so that higher design variations of the hull can be achieved. Each section consists of keel line, deck line, chine line and station line(s) that are represented using cubic Bezier curves and these lines are called feature curves. 3D surface model of a yacht hull is obtained by generating the Coons patches on the feature curves. Shape operators are also introduced and implemented for the modification of the given hull shape while considering some quality criteria such as hull fairness. Experiments in this study shows that variety of hull shapes can be generated using the proposed design framework with the application of the shape operators.

Citation (BibTeX)




CAD Tool - ModiYacht

Modi Yacht is a CAD tool which is developed to perform parametric and adjective based modification of yacht hull forms. Modi Yacht consists of three different modules: parametric-based modeling, adjective-based modeling and hull hydrostatics. Parametric-based modeling helps its user to perform instantaneous design modification in their hull designs. User can create wide variety of designs for yacht hull and can transform one type of hull to a complete different type. For parametric modeling, Modi Yacht uses the combination of traditional and custom made design parameters. It helps its user to fully integrate with the design to modify both minor and major features of yacht hull form such as, width (Beam), Depth, Length, Chine positions, entrance angle, station concavities, etc. Adjective-based modeling ability of ModiYacht enables the designers to create desired number of designs based on the predefined adjective. User can select single or multiple adjectives based hull forms. The generation of these models is autonomous, user has to define N number of design and select desired adjectives. This modeler performs uniform sampling in the defined design space and automatically generate adjective based designs. User can also calculate the hydrostatic results and form coefficients of their modified designs. 


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