surface group

[Mr. Stefan Pietsch 0]

Good morning,

 

I am trying to create a surface group out of several subsurfaces. But for some reason it does not work. I have watched the "Surface Group" sample and can not find a difference to the way I do.

 

I attached an extract of the model to show the problem.

 

 

best regards

example.fdbc

[Mr. Mattia Brenner 6]

Dear Stefan,

 

I opened your project and I can find no problem. The surface group is there and it contains all the imported surfaces (see screenshot). What is it exactly that you feel doesn't work?

 

Is there anything specific that you want to do with the surface group?

 

Cheers,

Mattia

[Mr. Stefan Pietsch 0]

Hey Mattia,

thanks for your reply. You are right. I understand that my problem is not caused by the surface group it depends on the next step. The aim is to create a surface group and than convert it into one panelmesh via mesh engine. Therefore I tried to make an image surface group out of the surface group. But not all subsurfaces of the group are included in the new image surface group. Maybe there is some problem about the surface structure orientations?

Again I attached an explaining example

Greetings,

Stefan

example.fdbc

[Mr. Stefan Pietsch 0]

I wonder if an image surface group is the right way to get a panelmesh for potential flow calculation. Maybe it is better first to put the subsurfaces together in a polysurface and than use this surface as source for the mesh engine!? I checked the orientations of the single surfaces. But I am not able to get a polysurface out of the subsurfaces (to see in the example I attached above).

[Mr. Mattia Brenner 6]

Dear Stefan,

 

as you already noted in the last post, what you are actually trying to do is combine all your surface patches into a single surface. The right object type for this is the polysurface. The surface group is merely a container for several surfaces and can e.g. be used to easily apply the same transformation to several surfaces or generate a section group.

 

Unfortunately, it is quite tedious to combine such a large number of surfaces into a polysurface. The orientation of the surfaces has to be consistent. Additionally, you need well ordered rows and columns of surfaces. It would require multiple steps for this case and I wouldn't recommend it. My suggested procedure is to create sections with the surface group and loft/skin them with a new surface. See what I did in the attached project file. I used a feature for the lofting which is also supplied with the Framework. However, I have revised it and will exchange the supplied feature for the next Framework version.

 

For slightly better results you can also do separate surfaces e.g. treat flat of bottom and flat of side separately. See approach2 in the project file.

 

Hope this helps. Cheers,

Mattia

 

example_MB.fdbc

[Mr. Stefan Pietsch 0]

Hi Mattia,

 

I have tried your recommended procedure and it works very well. Thank you for that hint!

 

Now another question came up. How can I create sections in horizontal direction? I tried to set the option "section plane" within the "section group" dialog but it does not work to change something. As to see in the file it is not usefull to make vertical sections for some specific areas. Therefore I would like to create horizontal ones.

 

Again I attached an regarding example file.

 

 

Greetings,

 

Stefan

example.fdbc

[Mr. Mattia Brenner 6]

Hi Stefan,

 

yes, you can create horizontal sections, too. You have to create a plane (in the menu just below the section group) with the normal in z-direction and assign it in the section group. Of course, you can also create planes in any other arbitrary direction.

 

Cheers,

Mattia

[Mr. Stefan Pietsch 0]

Good morning Mattia,

 

I have managed to create horizontal sections via a section plane. For the upper part of the model (in the last example file) that is very usefull. Thanks for that hint.

But I still have problems to find the right tool or strategy to mesh a part of the geometry. In the attached example you can find the geometry I speak about. So I am asking if you could give me some support regarding the right meshing strategy and how to manage it within the FFW.

 

Not to strain your patience that should be the last question before christmas ;-)

 

greetings,

 

Stefan

 

example.fdbc

[Mr. Mattia Brenner 6]

Hi Stefan,

 

here is something that I would probably do. It does not look completely perfect, but is probably good enough for a potential flow computation (which I assume you need the mesh for). If you allow it to be even a bit more rough, then you could do everything with only one surface and mesh.

 

Cheers and happy holidays,

Mattia

example3_MB.fdbc

[Mr. Stefan Pietsch 0]

Thank you very much!

 

I think for the requirements of a potential flow calculation it definitely satisfies the needs. I will try to reproduce your steps and use it for the remaining areas. Right now I wonder where to find the "bulbsection" feature that you used.

 

Happy Christmas to you and your colleagues!

[Mr. Stefan Pietsch 0]

Dear Mattia,

 

I tried to use a modified version of the "bulbSections" feature for the upper part of the foremost hull part. But as you can see in the attached image some gaps appeared and I am not able to get them closed. Could you give me some advise how to close them?  Below I attached an example modell structure.

 

 

 

best regards,

 

Stefan

example.fdbc

[Mr. Claus Abt 14]

The upper edge of the lower surface is not at z=const. I.e. the construction of the lower surface needs to be done based on offsets that are cut at the height of the first horizontal one for the upper part.

 

Cheers

Claus

[Mr. PRABU DUPLEX 0]

Dear Stefan,

 

as you already noted in the last post, what you are actually trying to do is combine all your surface patches into a single surface. The right object type for this is the polysurface. The surface group is merely a container for several surfaces and can e.g. be used to easily apply the same transformation to several surfaces or generate a section group.

 

Unfortunately, it is quite tedious to combine such a large number of surfaces into a polysurface. The orientation of the surfaces has to be consistent. Additionally, you need well ordered rows and columns of surfaces. It would require multiple steps for this case and I wouldn't recommend it. My suggested procedure is to create sections with the surface group and loft/skin them with a new surface. See what I did in the attached project file. I used a feature for the lofting which is also supplied with the Framework. However, I have revised it and will exchange the supplied feature for the next Framework version.

 

For slightly better results you can also do separate surfaces e.g. treat flat of bottom and flat of side separately. See approach2 in the project file.

 

Hope this helps. Cheers,

Mattia

Dear Mattia,

 

I imported the IGES file created in NAPA after that I created the lofted surface according to your instructions as follows"My suggested procedure is to create sections with the surface group and loft/skin them with a new surface". After this step my surface is not even like the one I find in your file. 

 

Afterwards if I want to modify the bulbow bow and the hull can I use transformation functions after this step for the changes?

 

Regards,

D.Prabu.

[Mr. PRABU DUPLEX 0]

Dear Mattia,

 

I imported the IGES file created in NAPA after that I created the lofted surface according to your instructions. After this step my surface is not even like the one I find in your file. Please find my attached file.

 

Afterwards if I want to modify the bulbow bow and the hull can I use transformation functions after this step for the changes?

 

Regards,

D.Prabu.

[Mr. Mattia Brenner 6]

Hi Prabu,

 

somehow, this post of yours skipped my attention. It seems to me that the problems you are having are related to the fact that you are trying to skin the complete hull in one go. This will not work in areas like the front of the ship. Here you have separate sections on the bulb and in the stem or bow overhang area at the same x position The skinning surface is jumping up and down from one part to the other. You should skin the different areas separately, e.g. create sections only on the bulb and skin it. The same for stern bulb, stern overhang and bow overhang. The rest of the hull in between can be skinned with one surface.

 

When you have the surfaces fronm the skinning, you can create image surfaces and apply any transformation that you want.

 

Cheers,

Mattia