Patch find_bounding_box: guard empty contours (blank alpha fallback to full image bbox)

app.py

@@ -211,6 +211,21 @@ def load_triposg():
             _ip_path.write_text(_ip_text)
             print("[load_triposg] Patched image_process.py: rmbg_net None guard")
 
+        # Patch find_bounding_box: guard against empty contours (blank alpha mask).
+        # When RMBG produces an all-black mask, findContours returns [] and max() raises.
+        # Fallback: return the full image bounding box so pipeline can continue.
+        if "empty_contours_guard" not in _ip_text:
+            _ip_text = _ip_path.read_text()
+            _ip_text = _ip_text.replace(
+                "    max_contour = max(contours, key=cv2.contourArea)",
+                "    if not contours:  # empty_contours_guard\n"
+                "        h, w = alpha.shape[:2]\n"
+                "        return 0, 0, w, h\n"
+                "    max_contour = max(contours, key=cv2.contourArea)",
+            )
+            _ip_path.write_text(_ip_text)
+            print("[load_triposg] Patched image_process.py: empty contours guard")
+
     # Safety net: patch inference_utils.py to make diso import optional.
     # Even if diso compiled with submodules, guard against any residual link errors.
     _iu_path = triposg_src / "triposg" / "inference_utils.py"