1. Symptom
When I tried to build qt 5.15 , I always obtain the following ERROR message:
1 2 3 4 5 6 7 8 9 10 Project ERROR: Library 'assimp' is not defined. make[4]: *** [Makefile:85: sub-assimp-install_subtargets] Error 3 make[4]: Leaving directory '/opt/qt/qt-everywhere-src-5.15.12/qtquick3d/src/plugins/assetimporters' make[3]: *** [Makefile:59: sub-assetimporters-install_subtargets] Error 2 make[3]: Leaving directory '/opt/qt/qt-everywhere-src-5.15.12/qtquick3d/src/plugins' make[2]: *** [Makefile:206: sub-plugins-install_subtargets-ordered] Error 2 make[2]: Leaving directory '/opt/qt/qt-everywhere-src-5.15.12/qtquick3d/src' make[1]: *** [Makefile:62: sub-src-install_subtargets] Error 2 make[1]: Leaving directory '/opt/qt/qt-everywhere-src-5.15.12/qtquick3d' make: *** [Makefile:378: module-qtquick3d-install_subtargets] Error 2
2. Reason
Why? Please refer to QT5.15在Ubuntu22.04上编译流程 .
3. Solution
Modify line 13 of /opt/qt/qt-everywhere-src-5.15.12/qtquick3d/src/plugins/assetimporters/assimp/assimp.pro from QMAKE_USE_PRIVATE += assimp to QMAKE_USE_PRIVATE += quick3d-assimp.
Don't use assimp-5.2.2 from Ubuntu default repo, but build and install assimp (5.2.3 or above) from source.