f3d file structure for fluids

[Kostadin Petkov]

Hello!

Currently I'm developing f3d import/export for my fluid sim engine.

I need some file structure specification that describes how to export/import velocity/temperature/(and so on) values in a standard way, understandable for other simulators.

Regards,

Kostadin Petkov

[Magnus Wrenninge]

I'm sure others can pitch in with their experience, but in general it's just a matter of putting the appropriate 'attribute' string on each field. The 'name' string can be set to whatever is appropriate. For example:

root/

  liquid_solver : v (MACField)

  liquid_solver : levelset (SparseField)

or

root/

  gas_solver : v (MACField)

  gas_solver : density (SparseField)

When you read an .f3d file from disk, you could then use 

  Field<float>::Vec scalars = in.readScalarLayers<float>();

  BOOST_FOREACH (Field<float>::Ptr i, scalars) {

    if (i->attribute == "density") {

      m_density = i;

    }

    // etc...

  }

  Field<Vec3f>::Vec vectors = in.readVectorLayers<float>();

  BOOST_FOREACH (Field<Vec3f>::Ptr i, vectors) {

    if (i->attribute == "v") {

      m_velocity = i;

    } 

    // etc...

  }

Hope that helps.

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[Kostadin Petkov]

Well it is something, thanks a lot!

I guess I have to reverse eng. some files and figure out them myself. If someone has papers on this it would be great!

Regards, 

Kostadin

[Sosh Mirsepassi]

You can also look at the maya export plugin under:  https://github.com/imageworks/Field3D/tree/master/contrib

If you have access to houdini distribution you can also find a import/export code under their "toolkit/samples/field3d"

-Sosh

--

[Kostadin Petkov]

Im currently trying to import a simple frame exported with FumeFX without any success.

It seems like they are using some custom filters.

In : 

Field<float>::Vec inpLayers = in.readScalarLayers<float>();

that later calls H5Z_pipeline i got issue_error equal to true

H5Z_pipeline(...) {

....

 if(pline->filter[idx].name)

                        HGOTO_ERROR(H5E_PLINE, H5E_READERROR, FAIL, "required filter '%s' is not registered", pline->filter[idx].name)

with filter[idx]._name == "ffxrle" (filter number is 256)

}

according to : http://www.hdfgroup.org/HDF5/doc/H5.user/Filters.html  it seems like they are making some own customization..

I'm using hdf5 v1_8_11 and trunk clone for field3d lib, both libs are build with MD x64 multibyte charset.

[Kostadin Petkov]

Excuse me for double posting. Thanks for the link! Contains good information that I'll use later.

[Kostadin Petkov]

My bad here. filter id is 641

[Oleg Bliznuk]

Hi Kostadin,
Have you read ffx cache data successfully ? Is it even possible ? Sorry, i am not familiar with hdf5 stuff, and dont know how exactly these custom filters act, so if the reading ffx data is possible, I will continue  my investigation :)
regards,
Oleg

[Lisur]

Hi Oleg,

have you noticed that latest release of FumeFX for Maya has option to use standard Deflate (gzip) filter in Field3D?

Regards

[Raiyan Haq]

How would one go about using this? I checked the dial but the file output is the same for me?