I’ve had the same problem building an Imaged database. I dug a bit into the code. in the directory (UE4 4.20.3) UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Source\GoogleARCoreBase\ you can find the file GoogleARCoreBase.Build.cs.
In this you can see where arcoreimage.exe is located and should be. On line 88 there are the following code
RuntimeDependencies.Add ("$ (EngineDir)/Plugins/Runtime/GoogleARCore/Binaries/ThirdParty/Google/ARCoreImg/" + ExecName);
There ExecName = “Windows/arcoreimg.exe”.
I also tested manually running arcoreimg (according to Google’s documentation The arcoreimg tool | ARCore | Google Developers)
I created a list file and copied in the current image directly to the directory where arcoreimg.exe exists.
Showed that there was no problem creating an imagedatabase. So what was the problem ???.
UE4 creates a temporary directory where it converts images to PNG as well as creates a file image_list_file.txt that contains name and filename (size if entered).
You can see where temporary directory location is by open CPP file …UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Source\GoogleARCoreBase\Private\GoogleARCoreAugmentedImageDatabase.cpp
temporary directory is …\UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Intermediate\ARCoreImgTemp.
The problem I can see is that the entire path for me to this directory is "D:\Program Files\Epic Games\UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Intermediate\ARCoreImgTemp\ it contains a space so arcoreimg.exe batch command look like this
arcoreimg build-db --input_image_list_path=D:\Program Files\Epic Games\UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Intermediate\ARCoreImgTemp\image_list_file.txt
–output_db_path=D:\Program Files\Epic Games\UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Intermediate\ARCoreImgTemp\something.imgdb
when UE4 tries to build with this string it will cut it right at the first space, it should be arounded with “” !!!
So I uninstall UE4 and install it again but now with C:\EPIC\UE_4.20 … … no space! now the path is C:\EPIC\UE_4.20\Engine\Plugins\Runtime\GoogleARCore\Intermediate\ARCoreImgTemp\
Now I have No trouble creating an image database with the example from google (AugmentedImages project).