Subject: [harryproa] Re:: BezierCAD solid modelling software and proa design
From: "cruisingfoiler@yahoo.com.au [harryproa]"
Date: 12/26/2014, 12:02 AM
To: <harryproa@yahoogroups.com.au>
Reply-to:
harryproa@yahoogroups.com.au

 

The key point with KSS is that the degrees of freedom are already restricted.  Flat panel topsides can only be curved along one axis.  For instance, flared topsides cannot become vertical (and vice versa) - twist / torturing is to be equated with compunding.  The reason I developed the software was to mathematically ensure fairness along hull lines whist modelling complex features such as radii and compounding.
There is no reason why the panels cannot finish short of the bow, enabling a more organic fairing of this region. Care must be exercised to ensure that the organic fairing harmonizes with the more clinical KSS features.
In my opinion, seamlessly flaring topsides from flat panels entails stopping the topsides well short of the bow in order to introduce compounding.  If this stricture is embraced, then the remaining area for organic fairing is in the compounded / radiused areas.
Referring specifically to my design, the shape of the compounded regions (exclude the deck line windward stem for the moment) involves a minor modification to the initial hull lines.  Initially the hull lines are conceived for a straight stem intersecting with keel and deck centreline.  The principal hull lines are faired to these parameters.  The keel - stem and stem - deck intersections are then modified with a radius prior to the creation of sections, waterlines and buttock lines.  The bow of the windward hull is treated differently as this ares entails mathematically intersecting and fairing together flat panels and radius joins.  The weather rail deck radius describes the bow shape as it intersects the hull centreline.  The lee rail of the weather hull is mathematically faired to intersect with the weather panel.
It is doubtful that this fairing can be improved.  Building will either confirm or disconfirm this thesis.  Building will also confirm whether the panels will easily and seamlessly assemble.  I cannot at this stage advise which method will be quickest and easiest - time will tell.  My suggestion is that the topsides at the very least should continue right to the bow.
When it comes to a more organic fairing, it might be worth describing a particular bow shape at the design stage in order to establish that the feature can be assimilated.

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Posted by: cruisingfoiler@yahoo.com.au
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