Building Unreal Engine from Source = huge file size

My question is, why does the Unreal4 file folder balloon from 9 to 24 gigs when I build the engine from source? In particular, there seems to be a lot of additional files in the Engine / Intermediate folder (8 gigs) in comparison to the release version downloaded from the launcher (172 MBs).

I am not an experienced , so my knowledge of Microsoft Visual Studio is limited at best.

I followed the instructions in Epic’s documentation.

Downloaded version 4.8.3-release from Github and compiled a Development Editor build to Win64 with MVS.

Any clarification would be appreciated.

Hey zbuffer14-

The difference in file size is due to the source version including additional folders and files that are not required for the binary version. If you explore the Engine/Intermediate/Build/Win64/UE4Editor/Development folder for both directories you can see the difference in the files included in source versus binary.

Cheers

Hi .

Thanks for replying.

I’m just trying to build a slightly modified version of the Editor for my own use.

Is there a way to configure the build settings in MVS that will compile without these additional folders and files?

Hi zbuffer14,

Something you could try would be to delete the Engine/Intermediate folder after having built the Engine. The next time you open the Editor, it will take a little longer than usual as it rebuilds the parts of this folder that it needs. However, once that is done, you will have a much smaller folder and overall Engine size. Not quite the same size as the Binary Engine, but it will be significantly smaller than it was.

Keep in mind that if you do delete the Engine’s Intermediate folder, you will not be able to make any changes to the Engine’s source code and build the source code until you run GenerateProjectFiles.bat again. This will allow you to build the Engine again (which will require another full rebuild at this point), and then you can again remove the Intermediate folder to get the size back down a bit. In the case of your modified version of the Editor, you’ll want to make any source code changes before you delete the folder since it will be more time consuming to make changes to the source code after you delete it.

When I tried this myself, the Engine/Intermediate folder went from approximately 8 GB (after building the Engine) to approximately 9 MB (after deleting the Engine/Intermediate folder and then starting the Editor).

Thanks .

Hi again everybody,

Along these same lines. I’ve also downloaded and compiled the Unreal Tournament project and have noticed that this project file is a whopping 31 gigs – that’s after deleting the Engine / Intermediate folder.

Looking at the UnrealTournament content directory, its easy to see that approx 10 of those GB’s are coming from there. The Engine / DerivedDataCache is of course quite large. Both of those are non-negotiable.

With the knowledge that I don’t plan to modify code and re-compile again, what else can I possibly remove to get this project size down?

I am not sure if there is anything else that you can safely delete to reduce size on disk. Both the Intermediate and DerivedDataCache folders will be rebuilt when you open the project (and both should be at least a little smaller when this happens).

If you have no intention of working with code at all after initially creating the project, you may be able to delete the Source folder to save a little more space. However, I have never tested this, so I am not sure this is actually safe to do. In theory, once the project is built initially, all of the necessary code will be compiled into the project’s .dll file, so the source code itself is no longer necessary. Just remember that if you do delete this folder, you won’t be able to get it back. The other folders are all required, so don’t delete any of those.