No ideas at all..?

Okay, I managed to figure it out. Yes, this module is not available if using open source version of Qt but one can build it manually from source components and use.

This instruction helped me a lot: https://linzichun.com/posts/qt-mqtt-opcua-modbus-rest/#qt-opc-ua

Be ready to read the console, download some other missing stuff to your platform and repeat the same command, however. I needed to install about 4-5 missing utilities during the proccess.

Hi, I faced the same problem, failed to load OPC UA plugin:
qt.opcua: Failed to load OPC UA plugin: "open62541"
qt.opcua: Available plugins: QList("open62541")
Could not create client

I solved by putting libcrypto-3-x64.dll in the output build directory. Open62541_backend.dll depends on libcrypto-3-x64.dll, you can check it by using Dependency Walker tool.

My env: Qt 6.6.0, MSVC2019 64bit.

The combo described is the list of commands you use to build a Qt module. Since you are on windows, make will be either nmake if you are using Visual Studio or mingw32-make if your MinGW.

What do you mean by "add to Qt Creator" ? You will need to add the paths to their respective .dlls folder to the PATH environment variable in the Run part of the Project panel so they are found when running your application from Qt Creator.

There should be no need to add them to your project, everything should be handled by the module itself.

But no, you should first build and install the module and then build your project.

On a side note, I wouldn't name a project with something that resembles to a Qt class unless you plan to submit it for inclusion in the module ?

Hi
It uses ATL::CComPtr
all over so yes using visual stud and create a DLL might be only way as not
to drive u insane.

Do you need Qt for GUI or could u just use VS for whole project?