diff --color --unified --recursive --text trunk/CMakeLists.txt trunkb/CMakeLists.txt
--- trunk/CMakeLists.txt	2022-05-14 20:34:47.192388716 +0800
+++ trunkb/CMakeLists.txt	2022-05-14 20:39:24.137498634 +0800
@@ -1264,9 +1264,12 @@
 SET(YADE_LIB_PATH ${CMAKE_INSTALL_PREFIX}/${LIBRARY_OUTPUT_PATH}/yade${SUFFIX})
 SET(YADE_EXEC_PATH ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR})
 SET(YADE_PY_PATH ${YADE_LIB_PATH}/py)
-SET(YADE_DOC_PATH ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DATAROOTDIR}/doc/yade${SUFFIX})
-SET(YADE_MAN_PATH ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_MANDIR})
-
+IF (NOT YADE_DOC_PATH)
+  SET(YADE_DOC_PATH ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_DATAROOTDIR}/doc/yade${SUFFIX})
+ENDIF (NOT YADE_DOC_PATH)
+IF (NOT YADE_MAN_PATH)
+  SET(YADE_MAN_PATH ${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_MANDIR})
+ENDIF (NOT YADE_MAN_PATH)
 
 SET(CMAKE_SKIP_BUILD_RPATH FALSE)
 SET(CMAKE_BUILD_WITH_INSTALL_RPATH FALSE)