You've got the IFF file, that's a start!
You'll need to work your way through through the connected files to find the MSH file for the Krayt Skull. For some understanding on how these files are connected to one another I suggest checking out
HelmedRaven's Painting guide. Paintings lack an LOD, which the Krayt Skull has, but it will give you an idea of the file types. We are going to work in reverse, starting with the IFF and working out way to the MSH.
IFF >> APT >> LOD >> MSH >> SHT >> DDS
(You don't need the last two)
Start by opening SIE and navigating to Krayt skull IFF: object/tangible/loot/quest/shared_frn_quest_krayt_skull_01.iff
Hard Way:
(But informative)
Open the IFF file in the Editor (double click).
IFF:
Scroll through the chunks in the upper left window section to
STOT >> SHOT >> 0007. Then click through (or use the up and down arrow keys) to navigate until you find a chunk with the templates value of
appearanceFilename with the value of
appearance/poi_tato_skel_krayt_head_s01.apt
appearance/poi_tato_skel_krayt_head_s01.apt
Appearance is the folder, poi_tato_skel_krayt_head_s01 is the file name.
Navigate to the "appearance" folder in the Repository window of SIE and then search for "poi_tato_skel_krayt_head_s01" and hit enter. (No quotes) Double click on the poi_tato_skel_krayt_head_s01.apt file to open it in the editor.
Appearance:
To get the lod is easy, the appearance file has only one chunk called "NAME," click on it. On the right will be the value
appearance/lod/poi_tato_skel_krayt_head_s01.lod
Go to the appearance/lod folder in the repository and search for
poi_tato_skel_krayt_head_s01
(Paste the text in the box at the bottom and hit "Enter" on your keyboard)
One thing to note is that some files will retain their naming scheme from the appearance, so once you have the name of the apt file, you can just go straight to the appearance/mesh and search for it.
Lod:
The LOD file is what connects the different level of details for each model. For your purpose, you just want the l0 msh (Highest level of detail) You can find this under
DTLA >> 0007 >> DATA >> CHLD (last child). MeshID is 3, Mesh is
mesh/poi_tato_skel_krayt_head_s01_l0.msh
My handwriting is garbage with a mouse. (j/k, it's just garbage in general)
Mesh:
Go to the appearance/mesh folder and search for
poi_tato_skel_krayt_head_s01_l0 and then Extract the file.
That should be all you need. If you want the texture file, use the above steps to locate the Shader, then also locate the Texture DDS file.
Easy Way:
In SIE, right click on the IFF file in re Repository. Select "Extract Chain." Choose a folder, then hit "OK." Your computer may now die for a little bit as it extracts all the connected files. (Pretty intensive)
Go to the location you extracted the files. Go to the appearance folder, then the mesh folder. Look for the
_l0 mesh file. That's the highest level of detail mesh file for that model.
Extract Chain doesn't always work and sometimes dies a terrible death
Side Note:
When looking for an IFF file, something that can make life really easy is to search the
SWGEmu repo. (or MTG for NGE / CU stuff). I searched for "krayt skull" and it was the second result.