So I’d like to make changes to UE4 source code and not recompile the ENTIRE engine, but perhaps just the modules that I made changes to. I’d like to think there’s some to reduce the compile time if I only changed one value in a one file. Is this possible in MSVS or does it have to recompile everything anyways? Any feedback would be greatly appreciated.
As long as you are not hitting rebuild, this is already supported.
If you change cpp files only, generally you will only compile that module.
If you are changing header files though, any module that has a dependency on the module you changed will need to be recompiled. If this is a core module, there is really nothing you can do about this.
I’ll be a little bit more specific about what I did. I’m modifying the InertialScrollManager.h which means that any module which includes it will have to also be recompiled. When I rightclicked the UE4 Project in MSVS’s Solution Explorer and hit “Build,” it compiled around 500 modules (which seems a bit much for just the inertial scroll manager). The compile took more than 2 hours on mid-high tier computer. Which begs the question: is everything being recompiled? Is this wait time normal or am I just being impatient? If my procedure is incorrect, could you describe the appropriate workflow for what I want to do? I’d greatly appreciate it. 
I’ll be a little bit more specific about what I did. I’m modifying the InertialScrollManager.h which means that any module which includes it will have to also be recompiled. When I rightclicked the UE4 Project in MSVS’s Solution Explorer and hit “Build,” it compiled around 500 modules (which seems a bit much for just the inertial scroll manager). The compile took more than 2 hours on mid-high tier computer. Which begs the question: is everything being recompiled? Is this wait time normal or am I just being impatient? If my procedure is incorrect, could you describe the appropriate workflow for what I want to do? I’d greatly appreciate it.
One note here, playing with VS settings here won’t help you out at all. UE4 has it’s own build system called UBT and it ignores any settings in VS as well as project files (in fact you don’t need VS project file to build the game code, UBT only uses VS for compiler). He builds according to build scripts (C# files in source), so if you want effect compiling process you need to play with them
I myself don’t like fact that UE4 is direcly link to my module (but it makes sense as it becomes part of the engine) and when i rebuild it deletes whole engine bineries. I experiment a little but so far didn’t find the way to avoid that, so i will watch this question ;]
I believe there are about 1000 build steps for a full rebuild, so if you’re only seeing 500, there are definitely some being skipped. 2 hours though? Daaaaamn.
From what I understand, was trying to build the engine itself, which means it is built by VS, not by UBT.
But do correct me if I’m wrong. I am very new to this. Thanks!
Why source engine is different form the launcher engine?Do you have any idea about this one ?