The .pro file at https://code.qt.io/cgit/qt/qtdatavis3d.git/tree/examples/datavisualization/surface?h=5.15 depends on a file that is further up in the folder hierarchy: include( ../examples.pri )

However, if the example was installed to a write-protected location and the user chooses "Copy Project and Open", examples.pri is not copied over so the project cannot be built.