This question is more or less a warmup of this question:
how to get cmake to add files to msvcs solution tree
It never got a valid answer so I want to repose it slightly different:
Is it possible to use the cmake solution folders that where introduced with cmake 2.8.3 to add files directly to the vs solution? I want to do the cmake equivalent of VS->Solution->Add->Existing Item. So my file will appear in a folder that belongs to the solution and not to a project.
I found examples how the solution folders can be used to group targets into folders with code like this:
set_property( GLOBAL PROPERTY USE_FOLDERS ON)
set_property(TARGET ${TARGET_NAME} PROPERTY FOLDER "Test")
So can I add a file instead of a target to the folder?
This is probably not possible.
CMake organizes its assets into projects and targets. The project is what corresponds to Visual Studio's solution file while each target will generate a Visual Studio project inside the respective solution.
The problem is now that CMake does not allow to add files to CMake projects. In fact, a CMake project is little more than a collection of targets and offers almost no customization options. Hence the USE_FOLDERS option you mentioned can only be used to group VS projects inside a solution, but not single files.
The closest to what you ask would probably be to add a custom target that holds your files. However, this will still generate a VS project (which also contains a bunch of other stuff besides your files) inside the solution and not a plain folder.