Try using <SOURCE_DIR> - if this works we should update other build logic needing this info...

Author: starseeker

assetimport/CMakeLists.txt

@@ -16,14 +16,12 @@ if (ENABLE_ASSETIMPORT)
     set(Z_PREFIX_STR "brl_")
   endif (TARGET ZLIB_BLD)
 
-  set(ASSETIMPORT_SRC_DIR "${CMAKE_CURRENT_BINARY_DIR}/ASSETIMPORT_BLD-prefix/src/ASSETIMPORT_BLD")
-
   ExternalProject_Add(ASSETIMPORT_BLD
     URL "${CMAKE_CURRENT_SOURCE_DIR}/assimp"
     BUILD_ALWAYS ${EXT_BUILD_ALWAYS} ${LOG_OPTS}
     PATCH_COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/assetimport_CMake.patch
-    COMMAND ${CMAKE_COMMAND};-E;remove;${ASSETIMPORT_SRC_DIR}/cmake-modules/FindZLIB.cmake
-    COMMAND ${CMAKE_COMMAND};-E;copy;${CMAKE_CURRENT_SOURCE_DIR}/FindZLIB.cmake;${ASSETIMPORT_SRC_DIR}/cmake-modules/FindZLIB.cmake
+    COMMAND ${CMAKE_COMMAND};-E;remove;<SOURCE_DIR>/cmake-modules/FindZLIB.cmake
+    COMMAND ${CMAKE_COMMAND};-E;copy;${CMAKE_CURRENT_SOURCE_DIR}/FindZLIB.cmake;<SOURCE_DIR>/cmake-modules/FindZLIB.cmake
     COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/assetimport_MDLFileData.patch
     COMMAND ${PATCH_EXECUTABLE};-E;-p1;${PATCH_OPTIONS};-i;${CMAKE_CURRENT_SOURCE_DIR}/assetimport_ParsingUtils.patch
     CMAKE_ARGS