halmodel
Scribo Mare
program can I use and how is the planning.
Ron de Vos
P.C.
Scribo Mare skrev i meddelelsen <9j16ar$pgg$1...@wanadoo.fr>...
>Can somebody tell me how to take digital the offsets of a halfmodel. Which
>program can I use and how is the planning.
>Ron de Vos
A halve model, was one of the tools boatbuilders used to check for fair lines
and sometimes even as a kind of "3D-plan" to ensure that the boat could acturly
be build. Scale models was even used to point out to the shipbuilders that did
not understand drawings , ----- there are museums full of scale models that was
acturly used building fregates and warships.
A normal halve model are made from waterline slices that you can copy from the
waterline drawing, and after producing a fairly rough model the edges are soften
down to show a fysical model of the hull ; this is used in "rapid prototyping"
technikes even today, where you with some technikes glue section slices together
and fair the surface after that.
-------- If you digitize the waterline drawing of a boat plan you can print each
waterline with callibrating holes so each slice fit exactly, and if you know
that for one to five model that there shuld be 2 centimeter between each
waterline , you can print each waterline contour, glue the paper to a 2
centimeter thick board and cut from the lines and drill some callibrating
holes, ------ then you get a scale model quite easy after you faired the steps
even.
If you mark with chalk on your halve model, each frame you can even take a photo
from front and back of the model, and import that graphics into a CAD program,
and "digitize" with a normal mouse from the lines on the photo.
There are many way's to copy the lines of a halve model into a CAD
program, ------- but it's like doing things the wrong way around as you don't
need a halve model to be able to make CAD drawings.
It's like when someone offered full-scale drawings ask for a table of offset,
when a table of offset is a step on the way to get full-scale drawings ; you
don't need it when the job they are supposed for, allready are done with the
full-scale drawings.
Reverse enginering is the word I guess.
Have a nice day.
P.C.
Glenn Ashmore
surface and manually measure the coordinates. Herreschof built a device from
3 calipers mounted at right angles to do it. You could build a modern version
for about $3,000 using digital height guages. The more modern way is the Faro
Digital CMM (coordinate Measuring machine) Unfortunately, those things cost
a bunch of money. The new way is with a laser CMM but those are in the
$100,000 range.
You might check out how they do it at Mystic Seaport.
http://www.mysticseaport.org/public/collections/shipyard/half.model.pages/half-hull.ship.model%20.html
A large sophisticated industrial design studio or mold shop might have one.
You might be able to send the model to the Mystic Seaport museum and have them
measure it for you.
The really modern way is laser measurement
Scribo Mare wrote:
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack there
of) at: http://www.rutuonline.com
Robert Laine
machine. Talk nicely to the guys and they may measure it for free after
hours.
--
Amitiés / Regards
Robert Lainé
http://www.sailcut.com/ free sail and hull CAD
-------
"Scribo Mare" <scrib...@wanadoor.fr> wrote in message
news:9j16ar$pgg$1...@wanadoo.fr...
P.C.
Robert Laine skrev i meddelelsen <9j2a1k$sts$1...@wanadoo.fr>...
>The best is to find a mechanic machineshop equipped with a 3D measuring
>machine. Talk nicely to the guys and they may measure it for free after
>hours.
When a museum need to coup the lines of a real boat, it's often done by building
a frame round the hull, ------ marking the start of each section frame and the
right distance between. this mean that middle of stern line become the Y axis.
Then looking from the front the X axis become a long vertical plank from the
decided 0,0 point. ------------ If you on the X axis measure upverts vith a 90
deg angle, you get your first point describing the hull.
It's easy if the keel is absolutly strait, as then the bottom of the keel
describe the intire Y axis and you can then mark each meter or halve meter ,
follow a plank you carefully place 90 deg to the Y Axis generating the Xaxis,
but with a halve model it is proberly easyer to "move" the Y axis so it just
toughes the outmost point of the hull but still is paralell to the original Y
axis.
Best way to describe this, is if you placed the halve model in a box, marked
along top and bottom edges , place a ruler along two points and measure down
untill you meet the surface of the model ; aslong as you write down the markings
you also made on the ruler --- how far along the box edges and the actural
measure reach down , you just need to keep every 90deg angle , and write down
all measures in an tabel. ------- it will not be _exact_ measures, but the more
care, the more exact the measures will be.
P.C.
Maby the easyest way would be to place the halve model in a open box, where you
before have decided the lowest left corner as the origine point (0,0,0).
And where you marked along the edges. Then makong one ruler run paralell with
two of the sides and another one paralell with the two others ,you can right
away write down the X,Y cooerdinates and then measuring down from the rulers at
exactly that point, you get the last important Z axis measure.
Have a nice day.
P.C.
http://w1.1396.telia.com/~u139600113/
Jacques Mertens
more than the real full size boat.
As for software, we use Rhino and it reads those files.
On a budget: measure stations with a contour gauge, transfer to paper, enter
coordinates manually in any 3D program et voila! It becomes digital as soon
as you enter it in the computer . . .
Another way: draw lines as stations on the half model, take a good picture,
translate from raster to vector, enter the 2 views of in Rhino, click on
make3D from 2 views.
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
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