How to generate USDZ file again from ZIP file?

问题

Hello everyone I'm trying to unzip a USDZ file, modify a texture, and then zip the USDZ file again, but it breaks.

Is there any special way to zip the file back? Even if I decompress and compress again it stops working and has different file size.

I'm using no compression and no encryption to zip the file. One thing I have noticed is that the attribute "Needed to extract" for the USDZ file is "2.0 or later" while my new zip file value is "1.0 or later". Also the files in the original USDZ zip have some extra fields I cannot read or add to my new file.

What could be happening? Any help would be appreciated.

回答1:

First Step (unzip usdz file)

To unzip a usdz file in macOS Mojave use the following method (or if you don't have a Mac just use a Hackintosh):

• In Finder change the extension of .usdz file to .zip.
• Uncompress .zip file using Archive_Utility.app or RAR_Extractor.app.
• Open unzipped directory and change the .png textures of your model.

Second Step (create usdz again)

Make sure that Xcode 10.2 is installed.

To convert a content of unzipped folder (binary usdc file and its textures) to usdz file format again, use the following command in Terminal.app:

cd ~/Desktop/Gramophone_Directory/


xcrun usdz_converter Gramophone.usdc Gramophone.usdz 
-g GramophoneMesh
-color_map Gramophone_Albedo.png
-metallic_map Gramophone_Metallic.png
-roughness_map Gramophone_Roughness.png
-normal_map Gramophone_Normal.png
-ao_map Gramophone_AO.png

And here are a full list of options (type xcrun usdz_converter -h in Terminal):

-g groupName [groupNames ...]        Apply subsequent material properties to the named group(s).
-m materialName [materialNames ...]  Apply subsequent material properties to the named material(s).
-h                                   Display help.
-a                                   Generate a .usda intermediate file.  Default is .usdc.
-l                                   Leave the intermediate .usd file in the source folder.
-v                                   Verbose output.
-f                    filePath       Read commands from a file.
-texCoordSet          set            The name of the texturemap coordinate set to use if multiple exist (no quotes).
-opacity              o              Floating point value 0.0...1.0

-color_default        r g b a        Floating point values 0.0...1.0
-normal_default       r g b a        Floating point values 0.0...1.0
-emissive_default     r g b a        Floating point values 0.0...1.0
-metallic_default     r g b a        Floating point values 0.0...1.0
-roughness_default    r g b a        Floating point values 0.0...1.0
-ao_default           r g b a        Floating point values 0.0...1.0

-color_map            filePath
-normal_map           filePath
-emissive_map         filePath
-metallic_map         filePath
-roughness_map        filePath
-ao_map               filePath

Hope this helps.

回答2:

To pack my modified USDZ file back, I used the tools provided here: https://github.com/PixarAnimationStudios/USD (usdzip) which works in Windows and Linux.

来源：https://stackoverflow.com/questions/55544185/how-to-generate-usdz-file-again-from-zip-file