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Re: S&G: Delftship panel shape development
By:HenkA
Date: 9/5/2007, 12:41 am
In Response To: Re: S&G: Delftship panel shape development (HenkA)

I just got a nice reply from Martijn van Engeland telling that the side of the Dave's kayak was not "developable". DelftShip has some checks that can be run to highlight the erratic area and detect such problems. So it was indeed pilot error, strictly speaking. I presume Dave will discuss Martijn's response later in detail.

Taking a step back, one could argue that for simple objects like kayaks there really should not have to be a "developability" issue. If you can describe a kayak as a set of lines from bow to stern and chop up the enclosed panels into smaller quadrilaterals and approximate them, that's pretty much all there is to it. You can get better resolution by interpolating the enclosing lines.

Reading up on developability I glanced at an article where it is related to mathematical conditions about Bezier surface patches leading to complicated mathematical feasibility conditions. This is quite difficult to understand. In my opinion, S&G kayak design should not have to bother with this because it is inherently simple and can be solved with simpler methods IMHO.

Having said that, I had to tweak the line interpolations of my designs too sometimes (but line interpolations are much simpler than surface interpolations), then again it was only for personal use, therefore imperfect.

Delft/FreeShip are great products and perhaps the only really usable S&G kayak design software available, for free even! That's something to be thankful for.

Henk

: Done. Since I got my PhD degree in Delft I can actually speak native. I'm
: curious what the math is behind their methods. Wish they had maintained
: the FreeShip name... that was at least a good start wasn't it?

: Henk

Messages In This Thread

S&G: Delftship panel shape development *LINK* *Pic*
Dave Reekie -- 9/3/2007, 4:35 am
Just a thought...
Jay Doorly -- 9/4/2007, 12:02 am
Re: S&G: Delftship panel shape development
Bryan Hansel -- 9/3/2007, 1:59 pm
Re: S&G: Delftship panel shape development
Bryan Hansel -- 9/3/2007, 2:05 pm
Re: S&G: Delftship panel shape development
Dave Reekie -- 9/3/2007, 2:12 pm
Re: S&G: Delftship panel shape development *Pic*
Duane Strosaker -- 9/3/2007, 1:26 pm
Re: S&G: Delftship panel shape development
Dave Reekie -- 9/3/2007, 1:37 pm
Re: S&G: Delftship panel shape development
HenkA -- 9/3/2007, 9:53 pm
Re: S&G: Delftship panel shape development
Robert McMurray -- 9/4/2007, 10:33 am
Re: S&G: Delftship panel shape development
Dave Reekie -- 9/4/2007, 11:14 am
Re: S&G: Delftship panel shape development
Robert McMurray -- 9/4/2007, 11:46 am
Re: S&G: Delftship panel shape development
Bill Hamm -- 9/5/2007, 2:19 am
Re: torture *Pic*
Robert McMurray -- 9/6/2007, 12:19 am
Re: S&G: Delftship panel shape development
Toni V -- 9/4/2007, 2:43 am
Re: S&G: Delftship panel shape development
HenkA -- 9/4/2007, 10:08 am
Re: S&G: Delftship panel shape development
Nick Schade - Guillemot Kayaks -- 9/4/2007, 11:01 am
Re: S&G: Delftship panel shape development
Dave Reekie -- 9/4/2007, 4:26 am
Re: S&G: Delftship panel shape development
Bryan Hansel -- 9/4/2007, 12:14 am
Re: S&G: Delftship panel shape development
HenkA -- 9/4/2007, 12:37 am
Re: S&G: Delftship panel shape development
HenkA -- 9/5/2007, 12:41 am
Re: S&G: Delftship panel shape development
David Reekie -- 9/8/2007, 8:11 am
Re: S&G: Delftship panel shape development
Bill Hamm -- 9/12/2007, 4:53 am
bending ply *Pic*
mike allen -- 9/12/2007, 11:57 am
Re: bending ply
Bill Hamm -- 9/16/2007, 3:20 am
Re: bending ply
Bryan Hansel -- 9/12/2007, 1:30 pm
s&g (developable) surf kayaks *Pic*
mike allen -- 9/12/2007, 2:23 pm
Re: s&g (developable) surf kayaks
Bryan Hansel -- 9/12/2007, 11:54 pm
another s&g (developable) surf kayak: *Pic*
mike allen -- 9/13/2007, 1:30 am
Re: another s&g (developable) surf kayak:
Bryan Hansel -- 9/13/2007, 7:13 pm
a s&g freeship surf kayak - the 'rail' *Pic*
mike allen -- 9/14/2007, 1:33 am
Re: a s&g freeship surf kayak - the 'rail'
Bryan Hansel -- 9/15/2007, 7:45 pm
some freeship techniques *Pic*
mike allen -- 9/16/2007, 3:46 am
Re: some freeship techniques
Bryan Hansel -- 9/17/2007, 5:04 pm
more freeship techniques *Pic*
mike allen -- 9/18/2007, 2:33 am
Re: more freeship techniques
Bryan Hansel -- 9/18/2007, 9:11 pm
control curve vs actual shape curve
mike allen -- 9/18/2007, 9:46 pm
Re: more freeship techniques
Bryan Hansel -- 9/18/2007, 9:07 pm
Re: more freeship techniques
Nick Schade - Guillemot Kayaks -- 9/18/2007, 8:56 am
corrupted curvature
mike allen -- 9/18/2007, 3:32 pm
Re: corrupted curvature
Toni V -- 9/19/2007, 6:49 am
Re: corrupted curvature
mike allen -- 9/19/2007, 2:42 pm
Re: corrupted curvature
Toni V -- 9/20/2007, 6:11 am
Re: corrupted curvature
mike allen -- 9/20/2007, 7:39 am
Re: corrupted curvature
Bill Hamm -- 9/18/2007, 6:43 pm
Re: corrupted curvature
Nick Schade - Guillemot Kayaks -- 9/19/2007, 12:56 pm
Re: corrupted curvature
HenkA -- 9/19/2007, 8:26 am
the magic *Pic*
mike allen -- 9/19/2007, 12:41 am
Re: Somebody has to ask....
TOM RAYMOND -- 9/19/2007, 12:16 pm
Re: Somebody has to ask.... *Pic*
mike allen -- 9/20/2007, 3:02 pm
Re: Somebody has to ask....
TOM RAYMOND -- 9/20/2007, 4:32 pm
some are a little more normal *Pic*
mike allen -- 9/21/2007, 3:58 am
Re: some are a little more normal
Bryan Hansel -- 9/21/2007, 8:33 am
Re: some are a little more normal
mike allen -- 9/21/2007, 12:16 pm
freeship sketch version of 'solitude 15' *Pic*
mike allen -- 9/22/2007, 6:33 am
freeship 'solitude 15' - 90 deg panel twist
mike allen -- 9/25/2007, 2:07 pm
Re: a s&g freeship surf kayak - the 'rail'
Ken Blanton -- 9/14/2007, 7:00 am
Re: a s&g freeship surf kayak - the 'rail'
mike allen -- 9/14/2007, 5:03 pm
'la ligne' - another s&g freeship surf kayak *Pic*
mike allen -- 9/14/2007, 2:18 am
Re: S&G: Delftship panel shape development
Bryan Hansel -- 9/5/2007, 1:09 pm
freeship is still continuing - at vers 2.78
mike allen -- 9/4/2007, 12:08 pm
Re: freeship is still continuing - at vers 2.78
Dave Reekie -- 9/4/2007, 1:43 pm
freeship stuff + vers 2.78 link *LINK*
mike allen -- 9/4/2007, 3:13 pm
Re: freeship stuff + vers 2.78 link
Toni V -- 9/5/2007, 4:04 pm
Re: freeship stuff + vers 2.78 link
mike allen -- 9/5/2007, 4:31 pm
Update *LINK* *Pic*
David Reekie -- 9/8/2007, 8:39 am
Update comments
mike allen -- 9/10/2007, 1:26 pm
Re: Update comments
Toni V -- 9/11/2007, 7:55 am
Re: Update comments
mike allen -- 9/11/2007, 11:55 am
Re: S&G: Delftship panel shape development
Toni V -- 9/3/2007, 10:27 am
Re: S&G: Delftship panel shape development
HenkA -- 9/3/2007, 9:42 pm
Re: S&G: Delftship panel shape development *Pic*
Robert McMurray -- 9/3/2007, 1:15 pm
Re: S&G: Delftship panel shape development
Dave Reekie -- 9/3/2007, 1:23 pm
Re: S&G: Delftship panel shape development
Robert McMurray -- 9/3/2007, 3:13 pm
Re: S&G: Delftship panel shape development
Dave Reekie -- 9/3/2007, 1:14 pm
Re: S&G: Delftship panel shape development
Toni V -- 9/3/2007, 2:47 pm
Re: S&G: Delftship panel shape development *LINK*
Daren -- 9/3/2007, 8:46 am