Update setup_blender.sh

setup_blender.sh

@@ -106,14 +106,17 @@ echo "Step 1: Installing PyTorch ${TORCH_VERSION} (for CUDA ${TARGET_CUDA_VERSIO
     --index-url ${TORCH_INDEX_URL} -vvv
 echo "PyTorch and Torchvision installation attempted."
 
-echo "Step 2: Installing flash-attn==${FLASH_ATTN_VERSION_TO_INSTALL} from PyPI (with --no-build-isolation)..."
-# Try to install flash-attn, letting pip search PyPI.
-# The --no-build-isolation flag allows it to see the already installed PyTorch.
-# We are NOT using --only-binary here to see if it attempts a source build and what error occurs.
+echo "Step 2: Installing flash-attn==${FLASH_ATTN_VERSION_TO_INSTALL} (binary only, no build isolation, checking PyTorch index)..."
+# Try to install flash-attn, strongly preferring a binary wheel.
+# --no-build-isolation allows it to see the already installed PyTorch.
+# --only-binary ":all:" tells pip to not attempt source builds for any package in this command.
+# --find-links adds PyTorch's index for this specific command, in case compatible wheels are there.
 "${BLENDER_PY_EXEC}" -m pip install --no-cache-dir \
     --no-build-isolation \
+    --only-binary ":all:" \
+    --find-links ${TORCH_INDEX_URL} \
     flash-attn==${FLASH_ATTN_VERSION_TO_INSTALL} -vvv
-echo "flash-attn installation attempted from PyPI."
+echo "flash-attn installation attempted."
 
 echo "Step 3: Installing remaining dependencies from ${UNIRIG_REQS_FILE_IN_SPACE}..."
 # Ensure flash-attn is REMOVED from unirig_requirements.txt.