I need help for creating hull surface in rhino

[itugemi]

Thank you for all answers again. I created a surface using section and waterlines like @TANSL say. I guess this is best way to generate this surface. I think it is enough for molding.

 

[ScottAmmon]

Hello,

I see that there are already lots of replies but I noticed not a lot of discussion about the 'Loft' command in Rhino which I think provides suitable results. This method is described in detail in the marine design training course offered by the creators of Rhino. You can use the 'Loft' command and select all of the section curves in order (starting fore or aft doesn't matter), often the 'Loose' or 'Normal' options allow for the smoothest fit through section curves.

Prior to lofting though, make sure that all of your section curves have the same number of points and degree of curvature; you can check this in 'object properties' of each curve. If they are not the same, 'Rebuild' them to utilize the same points and degree; this takes some time to make them fair and sized properly. 'CurvatureGraph' is the best tool for assessing fairness of the curves.

As far as the aft end of the skeg, you could try and extend the bottom portion of the sections immediately fore and aft of it and then after lofting use the ship's profile curve to trim the excess. You may also have to edit some surface control points to make the surface smooth. 'CurvatureAnalysis' is a good tool to view the overall fairness of a surface.

Hopefully this adds another method to your repertoire; there is no absolutely correct way to model a hull and many times combinations of all these tools can get you the results you need. If you would like some screenshots of examples i've done let me know. Good luck!

 

[TANSL]

Very good advice, ScottAmmon, which certainly will help to implement the "soft" command. Tedious process, but the process of smoothing of the shapes is always tedious.
The problem that arises here, in my opinion, is that in some hulls, use the horizontal sections (water lines) is much better than using the cross sections. Once this selection, your instructions will be very useful. But what is really important is to select the right curves.

 

[LP]

I also agree with Scott. I have not used Rhino consistently enough to have intimate knowledge to convey, but CAD software deal with discontinuities peculiarly sometimes. In your case, I would also consider having a control curve that intersects the discontinuity; an additional section cut to define the hull specifically at the corner. This may "assist" Rhino solving a fair solution for the hull surface at the location in point.

 

[TANSL]

I insist that it is best to choose a good system of curves "base". We must try to minimize the number of "tricks" to be applied to solve the problems, unnecessary, that we ourselves have created.
Before teaching how to use an application, it is preferable to teach how to use the brain.
Things we started complicated, can not be simplified and, if a method is too complicated, it is best to reject it and use another more rational.
But this is just one opinion, mine.

 

[LP]

I insist that it is best to choose a good system of curves "base". We must try to minimize the number of "tricks" to be applied to solve the problems, unnecessary, that we ourselves have created.
Before teaching how to use an application, it is preferable to teach how to use the brain.
Things we started complicated, can not be simplified and, if a method is too complicated, it is best to reject it and use another more rational.
But this is just one opinion, mine.

No comment.

Yeesh!

 

[rwatson]

No comment.

Yeesh!

I am going to use Rhino to design a pulpit for Tansl to preach from.
I think I will use the Loft command.

 

[TANSL]

I have to apologize because, apparently, my words have been too dogmatic. It was not at all my intention. I have not tried talking like a preacher in possession of the truth, but speak from the logic and common sense. I just wanted to say that it is better a little thought before boarding the solution of a problem, to give the right approach and choose the most effective solution.
Cheers

 

[Alexanov]

How to create a fair hull surface for this boat. I created a surface using patch command but it is not usefull for engineering .

http://msi.as/NurbsRecomendation.aspx - Read this. It is not about Rhino, but can help with NURBS.

 

[lqchinh]

Hey!

I attach a file for you where I created two surfaces. The key thing to both methods below is to first run curves along the hull as close to perpendicular to the sections as possible. using waterlines and buttocks usually doesn't work well here. While method number two benefits in accuracy from having many diagonals, method number one usually gives best results using few.

The first hull was created using the Surface from network of curves function in Rhino. It gives you a very accurate surface but it creates quite a lot of control points so it's difficult to point edit afterwards. This command has some limitations when it comes to deeper keels, say a full keel traditional sailboat as all the vertical and horizontal curves must intersect but two vertical or two horizontal curves must not. This surface took 4 minutes to create but it would benefit from some editing at the trailing edge of the keel.

The other surface is much less accurate but control points are few so point editing to perfection will be easy-ish. Surface number two was created using the t-splines plugin for Rhino. I simply appended faces in the areas between the curves.

There is also a picture of a third hull. This one was created exactly in the same way as your number two hull, using t-splines. I wanted to add a bulb to a previously designed hull. The old hull was designed using just curves, no surfaces whatsoever. When I wanted to add the bulb so creating a surface from the curves and sculpt the bulb into a NACA 0025 foil shape using yet another set of curves as templates seemed the easiest way to fair the bulb into the hull. I spent maybe 4 hours point editing and refining it and it could use yet another hour.

Can you upload third hull? and can you tell about strategy to create hull with tspline ? example, what do you use command? tsskin or tsloft.....