Hey,
Thanks for your reply. I fixed it, though it wasn´t what you and I thought it´d be.
First of all, it wasn´t a missing include. Because with a missing include, you dont get an unresolved external symbol, because the symbol itself cant be known then, so you would get a unkown identifier.
It also wasn´t a missing DependencyModule int the Build.cs, although I had experienced that modules aren´t always propagated through other modules.
(e.g. module1 adds dependency on module2, which has dependency on module3. If module1 also needs classes from module3, it needs to add it explicitly as dependency…)
At last it was a code failure. I use Visual Studio community 2017, which has a really bad IntelliSense performance, which is why I sometimes write the implementation of a method without the “generate method definition in cpp” functionality of Intellisense. And I forgot the class declaration UZEDFunctionLibrary:: before the GetPointCloudAtRoi(...) definition in the cpp file.
So the implementation of the method did not exist, which I did not recognize until I called it (if you dont call it, the compiler does not care whether a method has an implementation)^^