Remodeling Hull

Hello rurudyne,

I'm sorry I'm afraid i dont understand you. Are you referring to using several surfaces and then intersecting them, or overlapping several rows of control points??

So far I only used one surface for the hull, the keel is modeled with another one and the transom and the sheerline is trimmed.

 

Yes, several surfaces and intersecting them. The hull with its lines run out past where it intersects with the transom, just true to the indicated lines till the point of run out. Much as DC said.

As for the transom layer to intersect with that, what I was trying to say is that it's best to produce fair results if the control points on the transom closely match where they intersect with the hull layer. Since this is hard to predict I advise a shotgun effort where lots of very closely spaced horizontal lines are used in the transom layer and after intersection the ones that best match the hull kept but the rest removed as superfluous.

Now about getting all those horizontal lines...

As it has been pointed out that the surface of the transom may be conical I now think rotating a curved plane might be the wrong approach but instead, as I think you were indicating, and DC suggesting, matching the shape as best you can and then, it being extended past the hull, used a separate horizontal plane to intersect it to get all those horizontal lines in the transom layer before intersecting with the hull. That way you don't have to fuss about them.

Also, this thread reminded me of another on DelftShip forums from a while back: http://www.delftship.net/DELFTship/index.php/forum/hull-modeling/2014-transom-and-deck?limitstart=0

There may be some good advise to be found in there. Ummm ... don't pay much attention to what I wrote therein, I probably came off more confident than ability warranted... Possibly still do.

 

rurudyne thanks that thread is about basically the same problem.

This picture shows how the stern is supposed to look

 

It is no longer a replica since you are modifying the lines. It could be said the new boat is a re-interpretation.

 

When writing modyfing the lines what are you referring to? What if I left the sheer at original height?

I cannot imagine that it is possible to create a fair 100% nurbs match of an existing paperdrawn classic design.

 

I don't know what the limitations of the software are, but a replica implies identical shape, materials and construction techniques.

 

It is possible, though not always simple or straightforward, to create a NURBS surface which matches a set of lines within any desired tolerance, assuming the set of lines are self-consistent.

Some amount of interpretation is involved when an existing is boat is measured and a set of lines created. Also interpretation is generally involved when a set of lines is lofted and faired. This is true if traditional method are used or if "computer" methods are used.

I wonder how close the lines labeled "Elsie" which Botho is starting with are to the original Elsie.

 

This is the point I was hinting at David. Chapelle was well known to take liberties, some justified, others, not so much or pure speculation, in regard to lines. Elsie's lines are pretty typical of the indianhead variants of the era. I'll bet her lines are recorded elsewhere too. I personally don't understand the issue here, this is a common traditional counter stern (not a transom stern) and though some have more belly, others less, while others still, can even be compounded, still a simple set of problems to be worked out.

Every boat ever lofted, mechanically or digitally is an interpretation of the original. Only recently has it been possible to get the precision necessary, to insure all "reproductions" are precisely the same as earlier versions.

 

The Road To Spashing ... by F.A.Hayek's lesser known NA cousin

 

Botho in Maxsurf try three bonded surfaces for the hull and one for the deck, use another surface for the counter using that to trim hull and deck and the reverse for the stern surface.

 

Hello everyone,

i have high res scan of the plan now.


The problem is the accumulation of problems here.

1. the stern is very full. at the end it has a tumble home
2. In topview the stern is round. The sheerline flows into the stern fluently.
3. I need to model the Rail on the quarterdeck. i cannot bond the rail to a trimmed transom, which would be the normal way of modelling it....

I have not yet found out how to arrange, bond and or trimm several surfaces to reach this without gaps between surfaces or ugly side effects

One more question any idea how the avoid concave waterlines in the bow?

 

bhnautika

that idea looks interesting, i already tried a similar approach.
I hate bonded surfaces when there is no knckle between, always some problem with curvature...

would you use tangency?

But I dont understand what you mean with " reverse for the stern surface"

does your model have a round stern?

Thanks for your help

 

I will post my lines so you can bash around....

 

here a picture of the waterlines in the bow

 

In Maxsurf the solution might be to add one (or more) new column of control points near the bow. I think, if you try to Maxsurf, you are going to sweat blood. Try to do it with another application and, by .igs file, export it to Maxsurf.
Many Maxsurf users we always resort to this solution.