[Feature]: Support converting to and from .KF

[WasmachenDennSachenSo]

Expected behavior

The .kf file format as additional conversion option so that animation can be directly imported into Niftools (Blender Addon) or NifSkope without the need of an additional conversion via hkxcmd.

hkxcmd supports converting .hkx to .kf and vice versa. (LE Only)

https://www.niftools.org/pyffi/pyffi/formats/nif.html

[SARDONYX-sard]

I have been wanting to get one as well.

However, the following points made this impossible, so I did not implement it.

• I'm not sure of the detailed binary structure of the kf file.
• Currently I have modified serde (Rust's famous library) to somehow support conversion to hkx and xml
• The purpose of creating this was to analyze the file structure of hkx (log output for that) and to try to create an alternative to Nemesis

I had to write the following docs to analyze/output hkx binary data.

• Specification
• Binary analysis

If there are similar docs, I may be able to make it.

I looked at pyffi nif link, but my understanding and skills were not good enough to understand it. Sorry.

[WasmachenDennSachenSo]

https://github.com/niftools/nifxml/wiki

Maybe this can be of any use? You probably know this already tho ☺️

[SARDONYX-sard]

Hmmm, I am not sure of the correspondence between the information in hkx and kf.

I did find information that seems to be the case on the following page. (in the link you wrote).

• Extract data from binary .nif file using the nif.xml file description

Test data

./hkxcmd exportkf ".\meshes\actors\character\character assets\skeleton.hkx" ".\meshes\actors\character\animations\1hm_idle.hkx" "1hm_idle.kf"

• test output kf: x86_1hm_idle_test.zip

and then

./hkxc dump .\1hm_idle.kf -o .\1hm_idle_hexdump.kf.txt

00000000: 47 61 6d 65 62 72 79 6f 20 46 69 6c 65 20 46 6f  Gamebryo File Fo
00000010: 72 6d 61 74 2c 20 56 65 72 73 69 6f 6e 20 32 30  rmat, Version 20
00000020: 2e 32 2e 30 2e 37 0a 07 00 02 14 01 0b 00 00 00  .2.0.7..........
00000030: b8 00 00 00 53 00 00 00 01 00 01 00 01 00 04 00  ....S...........
00000040: 14 00 00 00 4e 69 43 6f 6e 74 72 6f 6c 6c 65 72  ....NiController
00000050: 53 65 71 75 65 6e 63 65 12 00 00 00 4e 69 54 65  Sequence....NiTe
00000060: 78 74 4b 65 79 45 78 74 72 61 44 61 74 61 17 00  xtKeyExtraData..
00000070: 00 00 4e 69 54 72 61 6e 73 66 6f 72 6d 49 6e 74  ..NiTransformInt
00000080: 65 72 70 6f 6c 61 74 6f 72 0f 00 00 00 4e 69 54  erpolator....NiT
00000090: 72 61 6e 73 66 6f 72 6d 44 61 74 61 00 00 01 00  ransformData....
000000a0: 02 00 03 00 02 00 03 00 02 00 03 00 02 00 03 00  ................
000000b0: 02 00 03 00 02 00 03 00 02 00 03 00 02 00 03 00  ................
000000c0: 02 00 03 00 02 00 03 00 02 00 03 00 02 00 03 00  ................
000000d0: 02 00 03 00 02 00 03 00 02 00 03 00 02 00 03 00  ................

Obviously kf is binary data as you can see from the reference link, but I am not sure how the data in hkx is converted to binary data in kf.

It remains unclear what each binary data in kf represents.

I looked at the src of hkxcmd a long time ago,

but it uses niflib, a C++ library, and I couldn't figure out what it was doing behind the scenes as well.

[SARDONYX-sard]

I finally understood what the document is about the other day.

It appears to be the following.

• The C++ type is written in XML, so it parses it and automatically generates the type.
• If binary data ClassName is written, it reads it as per the type information written in XML (deserialize. Once this is parsed, the serializer can do the reverse)

I am still not sure about hkxcmd's Export.

Even if I were to implement it, I think I would have to fork serde_hkx because XML is GPL licensed.
And I am currently developing another program, so it is low priority.

I may work on it after that is done. :)