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Author Topic: How does UMODEL work?  (Read 1996 times)
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How does UMODEL work?
« on: September 22, 2016, 04:34 »

Might sound like a total random question, but how does UMODEL work?

So Umodel sees a package, lets say Bioshock Infinite "DCOM_WardensOfficeBSP" package?

I assume, it decompresses the package first, then it reads the uncompressed file to find the models and animations.

But here is the question, I open a package up in HXD and I see gibberish, I see numbers etc.

How is one able to look at an uncompressed UDK file and see where a model is at?

If I take a Bioshock Infinite package, open it up in HXD etc, I find at the beginning of DCOM_PRISONWARD package, names of materials, one is "BillBoard_Fat_N" with hex numbers of "42 69 6C 6C 42 6F 61 72 64 5F 46 61 74 5F 4E"

Where is the rest of the file etc? surely I can't take that one sentence of data and put it into a new file with a new extention?

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Re: How does UMODEL work?
« Reply #1 on: September 22, 2016, 16:44 »

UModel doesn't decompress package. The package is decompressed on-fly, with special kind of FArchive. For UE3 games it is performed in FUE3ArchiveReader. Now you can look for "new FUE3ArchiveReader" code in sources to understand remaining part.

Unreal package file format is very complex thing. You may find some information about the format in pages, which I collected on UModel's Github Wiki -

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