KCS bulb transformation tutorial

[Ms. Nabila Naz 0]

Can I get the step by step tutorial of the following sample for optimization? 

" KCS Bulb Transformation with Surface Delta Shift (B-Spline Surface)"

[Matthias Maasch 21]

Dear Nabila,

 

as far as I know there is no step by step tutorial for this sample. However, I would like to help to you to better understand this sample. First of all, please find below the general structure of this sample, which you would follow when setting up the project on your own:

 

1) Import the hull geometry - This could be an IGES, STL, Panelmesh or Offset file. You can import geometry into CAESES via File > Import > ...

 

2) Setup the transformation - Depending on the transformation you want to use, it is best practice to use sections (offsets) to visualise the outcome of the transformation rather than working with the IGES or STL directly. We recommend that because sometimes transformations can be expensive in terms of updating times. Another reason for this recommendation is that geometry changes are better to see when visualised sections-wise.

 

   2.1) Create sections via CAD > Offsets > Sectiongroup on the target part of the geometry. The number of sections should be as small as possible/ as high as necessary in order to visualise the change in geometry.

 

   2.2) Create a B-Spline Surface via CAD > Surfaces > More (the first one) > Planar B-Spline Surface. This would be based on your preferences. Position the initial surface roughly near your target parts and adjust the control points where necessary. Now choose some control points of the surface to be controlled by a set of parameters. In the sample project it is a single parameter dyBulb which controls only three control points of the surface.

 

By the way, if you would like to better understand our sample setups yourself, our "Show Dependency" function would probably help you a lot. You can use this function by right clicking (RMB) an object and choosing Show Dependencies. This is what I did to figure out how this delta surface actually works.

 

After creating and parameterising the B-Spline Surface create the surface delta shift transformation via CAD > Transformations >  Shifts > Surface Delta Shift. Set your delta surface and the target directions.

 

The transformation setup is now ready to use.

 

   2.4) Create an image offset group via CAD > Offsets > Image Offset Group and apply the previously created transformation in order to visualise the impact of the transformation on the geometry.

 

3) Create an image of your imported geometry and apply the previously created transformation. It is best practice to only use the parts of the imported geometry which are really affected by the transformation to reduce updating times. This is now your export object.

 

This should be it. Your other posts in the Forum indicating that you are working with Shipflow quite a lot. If you would like to use this transformation setup in order to send the resulting geometry to Shipflow you could work with offsets directly. Therefore create sections (offsets) on your geometry (number and distribution should be suitable for Shipflow) and transform those directly.

 

If you have further questions I would be happy to answer them.

 

Cheers

 

Matthias

 

 

 

[Ms. Nabila Naz 0]

Dear Matthias,

Thank you very much for your detailed instruction though it is not clear to me right now as I started using CAESES-free very recently; but I am trying to better understand your instructions. You have mentioned that " I  can better understand the sample setups by "Show Dependency" function by right clicking the objects"..does it mean the objects under the baseline?

Yes, I am working wiith Shipflow for 3 months and  I can perform  CFD simulation with it. At present, I want to optimize bulb of KCS using CAESES-free

so that I can optimize the resistance by Shipflow CFD simulation. As I am using Shipflow Design, it is not integrated with CAESES and in CAD > Transformations >  Shifts >

....there is only Lackenby shift option..no Surface Delta Shift option. For that, I think that if I can transform the bulb through CAESES and then import the new offset to shipflow can get CFD results for various bulb transformation. I am not sure whether is it possible or not? Would you please suggest me which path should I follow to get optimized result of Ship resistance for KCS hull with bulb transformation?

 

Best Regards,

Nabila Naz

[Matthias Maasch 21]

Hi Nabila,

 

 

You have mentioned that " I  can better understand the sample setups by "Show Dependency" function by right clicking the objects"..does it mean the objects under the baseline?

 

Yes. That's what I meant. In fact, you can use the "show dependencies" functions for other objects, such as configurations and computations as well. This function helps whenever a the dependency between some objects is not clear at first. In the dependency pop up window you are then able to choose between "show supplier/client" to see the downstream or upstream dependency.

 

 

Would you please suggest me which path should I follow to get optimized result of Ship resistance for KCS hull with bulb transformation?

 

I am guessing the integration of Shipflow in Shipflow Design is similar (if not the same) as in CAESES Free. So it should be possible for you to simply use CAESES Free as geometry generator and coupling tool with Shipflow. If I am wrong, please see the sample where the connection to Shipflow is shown.

 

Best regards

 

Matthias

[Mr. Dong Jiang 1]

Hi Nabila,

 

As the support engineer in China, I prepared some step-by-step tutorials for Chinese customers before. There is not a tutorials for KCS bulb transformation yet, but I hope something will help you in my tutorial.

 

My email address is caeseschina@163.com. Drop me a email and I will send you the tutorials and the corresponding project. 

 

Regards,

Daniel 

[Ms. Nabila Naz 0]

Hi Daniel,

Thanks a lot for your co-operation. Please check your email.

 

Regards,

Nabila Naz

[Ms. CHIARA NOTARO 0]

Dear Nabila,

 

I am testing the functionalities of the CAESES free version, I am a beginner and I would like to try changing the geometry of the bulb of a ship (imported in iges format), e.g. modifying the lenght/width.

Did you manage to make a bulb transformation without upgrading for the Free Form Deformation tool?

Can it be done following the steps written by Matthias? 

 

I read that you were referring to the specific tutorial " KCS Bulb Transformation with Surface Delta Shift (B-Spline Surface)" but I haven't find it....among the samples contained in the free version at the moment I only find "KCS Bulb retrofit" which is related to the upgraded version, only made by using FFD functionality...

 

Thank you very much

best regards

 

Chiara

 

 

[Jörg 29]

Hi Chiara,

 

The surface delta shift and curve delta shift are available in the free version. With this, you can apply changes to an imported geometry part. Check out the tutorial "hull variation" which explains how it works. The curve shift can be used also to change an existing bulb geometry.

 

Hope this helps...

Joerg

[Ms. CHIARA NOTARO 0]

Hi Joerg!

Thank you very much for your answer  :)

 

I will do that and give it a try..!!

 

Best regards

Chiara

[Mr. Carlo Pasquinucci 1]

Hey Chiara, 

if you need some more explanations, here there's a simple project with a bulb deformation with surface deltashift and "normal" delta shift.

You can check and use some ideas.

Cheers,

Carlo

ExampleForForum.fdbc

[Jörg 29]

I have just noticed that you have to switch on the scope visibility to see Carlo's setup. 

 

BTW: you can apply these transformations also to surfaces (e.g. from IGES files), and not only to triangulated data (STL).