Export meshed elements to GDF (WAMIT) file not successful

Coreform Cubit Importing/Exporting
#1

Hi, I am trying to export the elements to GDF which will be used for WAMIT.
image

However, the conversion failed.
It can be exported to an Abaqus inp file successfully.

image

Any mistake when I export to GDF?

Thank you very much!

#2

Hi @caiminbo. Welcome to the forum.

What version of Coreform Cubit are you using? What element types are you trying to export? If I remember correctly, GDF is primarily a surface element format. In the latest development version, the following works for me.

reset
brick x 10
mesh surface all
block 1 surface all
export gdf 'box.gdf' block 1 overwrite

Thanks,
Karl

#3

Hi, Karl,

Thanks for your reply!

I am currently using 2021.11 version.
If I use your example, it doesn’t work for me.

image
image1001×867 26.8 KB

I will try to upgrade to latest 2022.11 version and then try again.

Thank you very much!

Minbo

#4

Hi, Karl,

2022.11 works for GDF conversion. However, there are some problems when I import GDF file using other software.

Cubit file:

image
image730×494 69.5 KB

OrcaWave import GDF

image
image1074×812 254 KB

The Cubit file is attached here for your reference.

There are total 7879 elements, and 404 tri-elements among them.

Thanks!
Test2.cub5 (5.3 MB)

#5

Hi @caiminbo,

Users at Sandia National Laboratories did the testing for this. They likely did not test mixed triangle/quad meshes. Are you tied to this existing mesh?

How about this one?

delete mesh
mesh surface all

image

The element blocks are retained since the blocks were defined by the surfaces.

Also, as a side note, I found the empty element blocks confusing at first. Here is a little python script that deletes empty blocks that are defined by surfaces.

block_ids = cubit.get_block_id_list()
for block_id in block_ids:
    surface_owners = cubit.get_block_surfaces(block_id)
    if not surface_owners:
        cubit.cmd(f"delete block {block_id}")

You can either paste this into the tab in the command window or bring up the journal editor and switch into python mode and hit the play button.

image

I would be interested in knowing if the all-quadrilateral version loads correctly.

I will create a bug for your model and add it into our system.

Thanks,
Karl

#6

Hi, Karl,

Yes, it works for the all-quadrilateral version.

Below is the model imported from GDF file which was created by Cubit.

image
image711×477 93.3 KB

My model actual comes from a complicated meshed structural model and it includes some triangle elements due to many intersections with internal structures. Our engineers want to keep these tri-elements currently for easy load mapping later on.

If you will update your export GDF function, when will it be available?

Also, thanks for your sharing of “deleting empty blocks”.

Best Regards,

Minbo

#7

@caiminbo,

I don’t have a good answer on timing. We have several high priority projects right now that are going to take priority. Is this a commercial license? What organization has the license? That could influence priority.

Thanks,
Karl

#8

Hi, Karl,

The organization is “Technology Centre for Offshore and Marine, Singapore”.

Last year we have commercial + academic licenses, but this year we may only have academic licenses.

In this case, we may solve the issue by ourselves.

Thanks!

Minbo