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UE4 dependency issues with AIController

Link error: error LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl AAIController::AAIController(class FPostConstructInitializeProperties const &)" (__imp_??0AAIController@@QEAA@AEBVFPostConstructInitializeProperties@@@Z) Add AIModule as one of the project dependencies in the Build.cs file.

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iterator vector::end() returns funny result

So far this run-time error only happens in UE DevelopmentEditor environment. In a particular case, I used vector::find() to search for an element in a vector array. If it returned it = vector::end(), I pushed a new element…

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Compile error: missing “;” before “*”

This compile error is likely due to the absence of proper namespace…weird. Sometimes switching the build target between “DevelopmentEditor” and the others helps.

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Raycasting fails to avoid owner

UE4 uses a Collision-Trace-Channel system for raycasting (and physical collision). Interestingly, the Collision property is not only applied to “colliders”, but everything with a mesh. In order for the raycasting to work properly, you need to set the…

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UE4 crashes when started but the project is complied successfully

Runtime error may be caused by multiple reasons. First thing is to check the Log–usually it will not show much by default. Try print debug messages to the Log and track down the problem. Some tricky cases I…

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Compile fails / Cannot create MyUEProject.dll in VS2017

It may due to transferring files between systems. Delete everything under /Binaries and build again.

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dynamic_cast fails / RTTI not enabled

UE4 / VS2017 projects don’t enable RTTI by default, and VS2017 hides the configuration in Project Properties setting for UE4 projects. Workaround is to enable UseRTTI in the Build,cs file: bUseRTTI = true; Reference: https://answers.unrealengine.com/questions/55613/how-to-enable-rtti-when-compiling-a-plugin.html

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Undefined reference to vtable

Even though the compiler says “a missing vtable usually means the first non-inline virtual member function has no definition”…but usually it is not. The really error can be: IDE fails to include cpp files. Or, Forgetting a body…

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UE4 project creation / Compile errors

Having VS 2015 Community & VS 2017 Community installed. Install C++ support for VS 2015. Create UE4 project as usual, then switch the external tool to VS 2017. Or, Uninstall VS 2015 completely with this program. Don’t try to…

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