https://src.fedoraproject.org/rpms/prusa-slicer/raw/rawhide/f/prusa-slicer-openexr3.patch
--- a/cmake/modules/FindOpenVDB.cmake
+++ b/cmake/modules/FindOpenVDB.cmake
@@ -326,28 +326,10 @@ macro(just_fail msg)
   return()
 endmacro()
 
-find_package(IlmBase QUIET COMPONENTS Half)
-if(NOT IlmBase_FOUND)
-  pkg_check_modules(IlmBase QUIET IlmBase)
-endif()
-if (IlmBase_FOUND AND NOT TARGET IlmBase::Half)
-  message(STATUS "Falling back to IlmBase found by pkg-config...")
-
-  find_library(IlmHalf_LIBRARY NAMES Half)
-  if(IlmHalf_LIBRARY-NOTFOUND OR NOT IlmBase_INCLUDE_DIRS)
-    just_fail("IlmBase::Half can not be found!")
-  endif()
-  
-  add_library(IlmBase::Half UNKNOWN IMPORTED)
-  set_target_properties(IlmBase::Half PROPERTIES
-    IMPORTED_LOCATION "${IlmHalf_LIBRARY}"
-    INTERFACE_INCLUDE_DIRECTORIES "${IlmBase_INCLUDE_DIRS}")
-elseif(NOT IlmBase_FOUND)
-  just_fail("IlmBase::Half can not be found!")
-endif()
 find_package(TBB ${_quiet} ${_required} COMPONENTS tbb)
 find_package(ZLIB ${_quiet} ${_required})
 find_package(Boost ${_quiet} ${_required} COMPONENTS iostreams system )
+find_package(Imath CONFIG)
 
 # Use GetPrerequisites to see which libraries this OpenVDB lib has linked to
 # which we can query for optional deps. This basically runs ldd/otoll/objdump
@@ -398,7 +380,7 @@ foreach(PREREQUISITE ${_OPENVDB_PREREQUISITE_LIST})
     set(OpenVDB_USES_LOG4CPLUS ON)
   endif()
 
-  string(FIND ${PREREQUISITE} "IlmImf" _HAS_DEP)
+  string(FIND ${PREREQUISITE} "OpenEXR" _HAS_DEP)
   if(NOT ${_HAS_DEP} EQUAL -1)
     set(OpenVDB_USES_ILM ON)
   endif()
@@ -429,11 +411,7 @@ if(OpenVDB_USES_LOG4CPLUS)
   find_package(Log4cplus ${_quiet} ${_required})
 endif()
 
-if(OpenVDB_USES_ILM)
-  find_package(IlmBase ${_quiet} ${_required})
-endif()
-
-if(OpenVDB_USES_EXR)
+if(OpenVDB_USES_ILM OR OpenVDB_USES_EXR)
   find_package(OpenEXR ${_quiet} ${_required})
 endif()
 
@@ -450,7 +428,7 @@ endif()
 set(_OPENVDB_VISIBLE_DEPENDENCIES
   Boost::iostreams
   Boost::system
-  IlmBase::Half
+  Imath::Imath
 )
 
 set(_OPENVDB_DEFINITIONS)
@@ -460,10 +438,7 @@ endif()
 
 if(OpenVDB_USES_EXR)
   list(APPEND _OPENVDB_VISIBLE_DEPENDENCIES
-    IlmBase::IlmThread
-    IlmBase::Iex
-    IlmBase::Imath
-    OpenEXR::IlmImf
+    OpenEXR::OpenEXR
   )
   list(APPEND _OPENVDB_DEFINITIONS "-DOPENVDB_TOOLS_RAYTRACER_USE_EXR")
 endif()
