CMake: fix hdEmbree.dll deployment path -- copy to usd/ not exe root

plugInfo.json declares LibraryPath '../hdEmbree.dll', relative to usd/hdEmbree/,
so the DLL must live at usd/hdEmbree.dll. The previous POST_BUILD copied it to
the exe root, causing the module-not-found error at load time.

Fix: copy hdEmbree.dll into usd/ for POST_BUILD and install(). embree3.dll
stays in the exe root where Windows DLL search finds it as a dependency.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CMakeLists.txt

@@ -15,24 +15,35 @@ find_package(OpenUSD REQUIRED)
 find_package(Imgui REQUIRED)
 find_package(Glad REQUIRED)
 
-# User-supplied Embree SDK bin/ dir if Embree DLLs are not bundled inside USD lib/.
-set(EMBREE_LOCATION "" CACHE PATH "Embree SDK bin/ directory (leave empty if bundled in USD lib/)")
+# USD build that includes hdEmbree (built with PXR_ENABLE_EMBREE_PLUGIN=ON).
+# Can be a separate install from OpenUSD_ROOT_DIR; leave empty to search there instead.
+set(HDEMBREE_USD_ROOT "" CACHE PATH "USD build containing hdEmbree plugin (separate from OpenUSD_ROOT_DIR)")
+# Only needed if embree*.dll are not inside HDEMBREE_USD_ROOT/bin.
+set(EMBREE_LOCATION "" CACHE PATH "Embree SDK bin/ directory (leave empty if bundled in HDEMBREE_USD_ROOT/bin)")
 
 # ── hdEmbree detection ───────────────────────────────────────────────────────
-set(HDEMBREE_PLUGIN_DIR "${OpenUSD_ROOT_DIR}/plugin/usd/hdEmbree")
+if(HDEMBREE_USD_ROOT AND EXISTS "${HDEMBREE_USD_ROOT}")
+    set(_hdembree_root "${HDEMBREE_USD_ROOT}")
+else()
+    set(_hdembree_root "${OpenUSD_ROOT_DIR}")
+endif()
+
+# hdEmbree.dll lives at plugin/usd/hdEmbree.dll; the subdir holds only plugin metadata.
+set(HDEMBREE_PLUGIN_DIR "${_hdembree_root}/plugin/usd/hdEmbree")
+set(HDEMBREE_DLL        "${_hdembree_root}/plugin/usd/hdEmbree.dll")
+
 if(EXISTS "${HDEMBREE_PLUGIN_DIR}")
     set(OPENUSD_HAS_EMBREE TRUE)
     if(EMBREE_LOCATION AND EXISTS "${EMBREE_LOCATION}")
         set(_embree_dll_dir "${EMBREE_LOCATION}")
     else()
-        set(_embree_dll_dir "${OpenUSD_ROOT_DIR}/lib")
+        set(_embree_dll_dir "${_hdembree_root}/bin")
     endif()
-    file(GLOB EMBREE_DLLS
-        "${_embree_dll_dir}/embree*.dll"
-        "${_embree_dll_dir}/tbb12.dll")
+    # Skip tbb*.dll — already supplied by the main USD install to avoid conflicts.
+    file(GLOB EMBREE_DLLS "${_embree_dll_dir}/embree*.dll")
 else()
     set(OPENUSD_HAS_EMBREE FALSE)
-    message(STATUS "hdEmbree: NOT found — rebuild USD with PXR_ENABLE_EMBREE_PLUGIN=ON to enable")
+    message(STATUS "hdEmbree: NOT found — set HDEMBREE_USD_ROOT to a USD build with PXR_ENABLE_EMBREE_PLUGIN=ON")
 endif()
 
 # Collect source files
@@ -99,7 +110,19 @@ if(WIN32)
         COMMENT "Copying runtime DLLs and USD plugins..."
     )
 
-    if(OPENUSD_HAS_EMBREE AND EMBREE_DLLS)
+    if(OPENUSD_HAS_EMBREE)
+        add_custom_command(TARGET UsdLayerManager POST_BUILD
+            # plugInfo.json has LibraryPath "../hdEmbree.dll" relative to usd/hdEmbree/,
+            # which resolves to usd/hdEmbree.dll — so the DLL must live in usd/, not exe root.
+            COMMAND ${CMAKE_COMMAND} -E copy_if_different
+                "${HDEMBREE_DLL}"
+                "$<TARGET_FILE_DIR:UsdLayerManager>/usd/hdEmbree.dll"
+            COMMAND ${CMAKE_COMMAND} -E copy_directory
+                "${HDEMBREE_PLUGIN_DIR}"
+                "$<TARGET_FILE_DIR:UsdLayerManager>/usd/hdEmbree"
+            COMMENT "Copying hdEmbree plugin..."
+        )
+        if(EMBREE_DLLS)
             add_custom_command(TARGET UsdLayerManager POST_BUILD
                 COMMAND ${CMAKE_COMMAND} -E copy_if_different
                     ${EMBREE_DLLS}
@@ -107,6 +130,7 @@ if(WIN32)
                 COMMENT "Copying Embree runtime DLLs..."
             )
         endif()
+    endif()
 endif()
 
 # Compiler warnings
@@ -148,8 +172,13 @@ install(FILES ${OpenUSD_ROOT_DIR}/plugin/usd/hdStorm.dll
 )
 
 if(OPENUSD_HAS_EMBREE)
-    install(FILES "${HDEMBREE_PLUGIN_DIR}/hdEmbree.dll"
-        DESTINATION bin
+    # Install to bin/usd/ so plugInfo.json's LibraryPath "../hdEmbree.dll" resolves correctly.
+    install(FILES "${HDEMBREE_DLL}"
+        DESTINATION bin/usd
+        OPTIONAL
+    )
+    install(DIRECTORY "${HDEMBREE_PLUGIN_DIR}"
+        DESTINATION bin/usd
         OPTIONAL
     )
     if(EMBREE_DLLS)
@@ -214,7 +243,7 @@ message(STATUS "hdEmbree support: ${OPENUSD_HAS_EMBREE}")
 if(OPENUSD_HAS_EMBREE AND EMBREE_DLLS)
     message(STATUS "Embree DLLs: ${EMBREE_DLLS}")
 elseif(OPENUSD_HAS_EMBREE)
-    message(WARNING "hdEmbree found but no Embree DLLs detected — set EMBREE_LOCATION to the Embree SDK bin/ dir")
+    message(WARNING "hdEmbree found but no Embree DLLs detected — set EMBREE_LOCATION to the Embree SDK bin/ dir or check HDEMBREE_USD_ROOT/bin")
 endif()
 message(STATUS "=======================================")
 message(STATUS "")