What is an “out-of-source” build?
When your build generates files, they have to go somewhere. An in-source build puts them in your source tree. An out-of-source build puts them in a completely separate directory, so that your source tree is unchanged. In the first example, an in-place build is performed, i.e., the binaries are placed in the same directory as the source code.
When your build generates files, they have to go somewhere. An in-source build puts them in your source tree. An out-of-source build puts them in a completely separate directory, so that your source tree is unchanged. In the first example, an in-place build is performed, i.e., the binaries are placed in the same directory as the source code.
CMake, you have the option of creating an ‘out of source’ build. This means that all files associated with the build will be created in a directory that is ‘outside’ the source tree. Note that it is strongly recommended to build vtk and vtkSNL related projects out of source. The main argument to support this: the source directories do not get “polluted” with all the build files. These can be numerous, between all the cmake-generated, custom builds (Windows), object files, binaries, executables, project files (Windows), etc.
