DEFCAR
HULL FORM DESIGN & GENERATION
DFFORM MODULE


Main features : 
  • design of any kind of ship forms 
  • interactive hull form modification
  • on-line  basic hydrostatics calculation 
  • DXF & IGES export/import
  • printer/plotter outputs
For a fast automatic generation, using a set of basic ships (templates), see ShipGen .

Surfaces to define the hull form
 
DFform uses surfaces for defining vessel forms. It allows the definition of the vessel in a continuous three-dimensional way which has many advantages:
  • Speed and easiness in modifications of the hull form. 
  • Fairing without errors. The system obtains forms  better faired than any other process. 
  • The surface is defined in a continue way instead of a discreet way. This fact implicates:
    • More accuracy and less errors in later processes.
    • The local modification of a zone is automatically transmitted to the surface, keeping the forms always faired.
  • The project of a vessel starting from another one already designed with DFform is very easy, fast and powerful.


 

Control points
 

The user governs the form of the surface moving its "control points". The system supports multiple surfaces (patches) connected between them for defining the forms as a whole. The connections between patches can be from several continuity rates.The system manages internally the modifications produced in one patch that can have an effect on the other ones. During the hull design process,the user can perform naval architecture calculations in an interactive way with the purpose of checking  the effect that the modifications in the forms have over the vessel main parameters: displacement, centre of buoyancy, coefficients, curve of areas, etc.

Interactive design of the hull form by moving the control points of the surfaces.

Green: sections before
modification. Grey: sections after modification.

Note the smoothness of
the surface change.
Right image: zoom.

At any time , 
the user can see 
the curvature 
diagram to make 
easy the checking
of the forms.

The hull form definition can be done in three ways
 

 
 

Identification
In this case, the user has already the forms from a pre-existing vessel and he wants to "input" them into DEFCAR system, making one "identification". This procedure is frecuently used in the practice by the shipyards. Firstly, the user must input some reference points of the forms. DFform, helped by the user, will adjust the surfaces to the reference points. The precision of the identification can be of the order of 1 mm, depending on the quality of the pre-existing forms.

Transformation
In this case, the user wants to design a new hull form, starting from another one previously defined with DFform. This is the fastest method for projecting. The system offers many tools to change the surfaces of a vessel previously designed with DEFCAR in order to obtain a new one. This way can produce very different forms from the base vessel with easy procedures.

Hullform creation
It can happen the case of a new kind of vessel with very different forms that impedes to use the forms of another previous project. In this case,  the process would be defining the streamlining of the vessel, the principal lines that limit the stern and bow bodies, etc. Later you will easily create the surfaces supported in these lines. This process will produce the hull form. After an interactive phase of form modification, moving the control points or making whole trasformations, you will obtain the desired forms.

Cintranaval-Defcar S.L.
Lauroeta Etorbidea, 4 48180 Loiu, Bizkaia (Spain)
Tlf: +34 902158081
Fax: +34 944638552
info@cintranaval-defcar.com