open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear All:

Now I'm generating the Mesh in the Urban Area (City). I had the 2m resolution data, and I want to generate the mesh with Default Edge Length equal to 2.

But when I started to generate the mesh by BlueKenue, on the window is shown that around 1.6 millions nodes will be generated in my mesh. And every time, when the process goes to 10%, the program crushed. I don't want to increase the cell size, because I would like to describe the narrow street in the city center with less than 4 meter wide.

So I would like to ask, is the "crush problem" because of there are some limitions of BlueKenue, for example, it only can generate the mesh with less than 1 millions nodes? Or I need to use more powerful computer? Or there are some other solutions to solve this problem by changeing some parameters?

And also, is it possible to generate the mesh of each district respectively, then combine them together? I imaged if it is possible, maybe there are some problems happened at the boundaries between each districts, how to solve it?

Look forward for reply

Best wishes,
Qiang MA
2014-5-6

Hi Qiang,

What is the ERROR message?

There are no hard coded limits to anything in Blue Kenue.
All memory is dynamically allocated.
That being said, if you are using the 32bit version there is 2 GigaBit limit to the available virtual address space. If you are running into this limit then you will need to move to a 64 bit operating system and use BlueKenue64.

However, 1.6 million nodes will take a long time to generate but it should not cause memory problems.
I suspect there is something else wrong.
Post your t3m file so I can investigate...

re: meshing each district separately:
You can supply any number of submeshes to the mesher so this is certainly a valid approach. One caveat is that the submeshes cannot overlap and there needs to be a "reasonable" space between them.

Cheers... Martin

Dear Martin:
Thanks for your reply.

I tried several times, but every time, when the process goes around 11%, the window change like this.



The "Coverage" equal to something...

Does it mean the process still running? I need to wait? Or it means the process stop?

Best wishes,
Qiang MA
2014-5-6

That I'm afraid you may have uncovered a bug.
The coverage can only be between 0 and 100.

Please post your t3m file here so I can investigate.

Martin

Thanks for your reply. I'm trying the BlueKenue with another test.

Later I will post here.

Thanks
Best wishes,
Qiang MA
2014-5-6

Dear Martin:

Here is my .t3m file. Please help me.



I really want to discribe the narrow streets in the downtown which are less than 4 meter wide. Hence I put Default Edge Length equal to 2.

Yesterday, I tried to generate the mesh with Default Edge Length equal to 3. It worked, but it can not discribe well the streets in downtwon.

Look forward for your reply.

Best wishes,
Qiang MA
2014-5-7

Dear Qiang

Your file is too large so you need to send it to martin directly to his mail or to upload it through a dynamic link.

Riadh

OK I see.

I will send him directly.

Best wishes,
Qiang MA
2014-5-7

Hi Qiang,

There are a couple of problems with your t3m file.

1. There is not enough space between the northern edge of your outline and 2 structures so I moved it out.

2. More seriously, you included the very large elevation pointset as hard points. Some of these points had negative values which caused problems with generating nodes. Mapping the bathymetry/elevations to your mesh is a separate step from creating the mesh. There are a couple of threads in this forum where this is discussed.

I've attached 2 versions of a corrected t3m file here.
Const2m.t3m generates a good mesh with 2m triangles all over.
Variable.t3m generates a good mesh with larger triangles in open areas.

Hope this helps... Martin

Thanks a lot.

Best wishes,
Qiang MA
2014-5-9