Hull Parametric Design Guidelines - novice questions

[Mr. Iorga Stefan 1]

Hello everybody,

 

I've just graduated Naval Architecture Faculty and I'm eager to study furthermore hull form optimization and CFD.

 

I just have skills in modeling double curvature surfaces using Rhino and Grasshopper and, I suppose, a good sense evaluating empirically a hull form definition.

 

My goal would be to switch from Rhino to Caeses -  to generate a full parametric hull geometry.

There are many examples in Caeses's tutorials, though, none regarding ”how to create a parametric hull design, step by step”.

 

Silly it may sound, but can you give me some directions?

 

Thank you very much!

[Jörg 29]

Hi,

 

Thanks for this post, this is a very good question. The reason for not having a step-by-step tutorial for a complex ship hull so far is that each hull shape is different in its details. This makes it difficult to provide a generalized recipe. With out yacht hull tutorial , we try to provide the general technique and idea of how we set up parametric hull geometries. But I also see that we can still improve this further to help users like you to get into CAESES much easier. We will think about it!

 

In the yacht tutorial, only one surface gets generated. For complex shapes the approach is identical, there are just different cross section definitions that are used for several surfaces. Have you checked out the parametric ship hulls in the samples section (documentation browser)? There you can find a good port folio of cross section definitions that you can re-use and modify for your own shapes.

 

Usually, the step-by-step procedure is as follows:

1. Create parameters for the main dimensions of the hull.
2. Create the basic curves (keel, deck, waterline, centerline contour etc) and connect the parameters from the first step to these curves.
3. Define cross section curves as feature definitions for the different parts of the hull, as shown in the yacht tutorial. Again, more examples are given in the samples section, such as section descriptions for bulbous bow, transom, skeg.
4. Create curve engines, and optional function curves for the input of the curve engine (feature definition). See also the meta surface tutorials.
5. Create meta surfaces for generating the surfaces by using these curve engines.

 

Let me know what you think about it. I really hope this information helps a bit.

 

Cheers

Joerg

 

[Mr. Mattia Brenner 6]

Hi Iorga,

 

Jörg just gave an excellent introduction. What I can add is a so called training model that we sometime use for our training courses (see the attached PDF). It is a bit more complex model that the yacht hull, but still relatively simple.

 

The idea is that the trainer would demonstrate some steps live and the attendees can then follow with the help of the summary on the slide. This means that the steps are not described is as much detail as in the tutorials. But maybe, after doing the simple yacht hull tutorial (and the other not specifically ship-related introductory tutorials to learn the basics), you can follow the instruction well enough. After you have worked on this model, you can study the sample hulls in CAESES to see how modeling was specifically done for different ship types. Hope it helps!

 

We have the plan to add some more ship modeling tutorials in the future, but as Jörg said, it is quite a complex topic, so we will see how exactly to solve this.

 

Cheers,

Mattia

FS_TRAINING_fastMonohull.pdf

[Mr. Iorga Stefan 1]

Hey,

 

Jörg, Mattia, thank you very, very much for your help.

I'll start with these, and hopefully, I will share with you my work soon enough.

 

Many thanks, Stefan. :)

[Karsten Wenzke 12]

Hey folks,

 

The Fast Monohull traning pdf is now included in CAESES 4.x.

 

You can find it in the tutorials section "Hull Design" of the documentation browser.

The name is Fast Monohull. 05_Fast_Monohull.pdf

 

Note that the tutorial which is included in CAESES will be reviewed and updated from time to time and therefore might be newer than the one attached.

 

Cheers,

 

Karsten

[Mr. Xavier Arosemena 0]

hello!

One question:

I am supposed to know the waterline location before modelling my hull in caeses?

I was expecting caeses to help me calculate the exact displacement (and waterline)...

Doesn't work like that?

Cheers,

 

Xavier

[Mr. Claus Abt 14]

Hi Xavier,

You can do it either way. If you want to specify the shape of the design waterline you also need to know where it is going to be. But you can design a hull differently and then ask CAESES for the floating condition for a given displacement.

Cheers

Claus

[Mr. Xavier Arosemena 0]

Great. Thanks Claus.