diff --git a/Tools/ModelTranslator/bl_decimate.py b/Tools/ModelTranslator/bl_decimate.py
index 11b8e753..21a309e0 100644
--- a/Tools/ModelTranslator/bl_decimate.py
+++ b/Tools/ModelTranslator/bl_decimate.py
@@ -1,5 +1,5 @@
 """Blender 内运行：FBX 减面到指定三角面数 + UV 重展（锐边 seam 或 Smart UV Project）。
-调用：blender -b --factory-startup --python bl_decimate.py -- <src.fbx> <out.fbx> <target_tris> [seam|smart]
+调用：blender -b --factory-startup --python bl_decimate.py -- <src.fbx> <out.fbx> <target_tris> [seam|smart|none]
 """
 import os
 import sys
@@ -28,6 +28,11 @@ UV_FLIP_TOL = 0.02      # 质量门：UV 翻转面占比超此值回退 smart_pr
 UV_OVERLAP_TOL = 0.08   # 质量门：UV 重叠面占比阈值（手工 UV 同口径约 5%，灾难性失败 >20%）
 
 
+def uv_gate_ok(flipped, overlap):
+    """UV 质量门：翻转与重叠占比都在阈值内。overlap 为 None（op 不可用）按 0 处理。"""
+    return flipped <= UV_FLIP_TOL and (overlap or 0.0) <= UV_OVERLAP_TOL
+
+
 def count_islands(n_faces, adjacent_pairs):
     """union-find 数 UV 岛：n_faces 个面，adjacent_pairs 为 UV 连续的面索引对。"""
     parent = list(range(n_faces))
@@ -199,8 +204,7 @@ def _do_unwrap(obj, mode, warnings):
     if mode == "seam":
         _unwrap_seam(obj, warnings)
         m = _collect_uv_metrics(obj)
-        overlap = m["overlap"] or 0.0
-        if m["flipped"] <= UV_FLIP_TOL and overlap <= UV_OVERLAP_TOL:
+        if uv_gate_ok(m["flipped"], m["overlap"]):
             m["mode"] = "seam"
             return m
         warnings.append("seam 展开质量不达标（翻转 %.1f%% 重叠 %s），回退 smart_project"
@@ -250,7 +254,13 @@ def main():
         if not within_tolerance(target, cur) and cur > target:
             warnings.append("修正 %d 轮后仍超差：%d 面（目标 %d ±3%%）" % (MAX_RETRY, cur, target))
 
-    uv_info = _do_unwrap(obj, unwrap_mode, warnings)
+    if unwrap_mode == "none":
+        # rizom 管线：跳过展开，UV 由后续 RizomUV 步骤生成
+        _clear_uv_layers(obj.data)
+        uv_info = {"mode": "none", "islands": 0, "fill": 0.0,
+                   "flipped": 0.0, "overlap": None}
+    else:
+        uv_info = _do_unwrap(obj, unwrap_mode, warnings)
     out_dir = os.path.dirname(os.path.abspath(out_fbx))
     os.makedirs(out_dir, exist_ok=True)
     # 仅导出合并后的对象；整场景导出会把 armature/empty 等非 mesh 带进 _low.fbx
diff --git a/Tools/ModelTranslator/tests/test_bl_decimate.py b/Tools/ModelTranslator/tests/test_bl_decimate.py
index 91269446..c73ca1bb 100644
--- a/Tools/ModelTranslator/tests/test_bl_decimate.py
+++ b/Tools/ModelTranslator/tests/test_bl_decimate.py
@@ -75,5 +75,22 @@ class TestFillRatio(unittest.TestCase):
         self.assertEqual(bd.fill_ratio([]), 0.0)
 
 
+class TestUvGateOk(unittest.TestCase):
+    def test_clean_passes(self):
+        self.assertTrue(bd.uv_gate_ok(0.0, 0.0))
+
+    def test_boundary_passes(self):
+        self.assertTrue(bd.uv_gate_ok(bd.UV_FLIP_TOL, bd.UV_OVERLAP_TOL))
+
+    def test_flip_exceeds_fails(self):
+        self.assertFalse(bd.uv_gate_ok(0.03, 0.0))
+
+    def test_overlap_exceeds_fails(self):
+        self.assertFalse(bd.uv_gate_ok(0.0, 0.09))
+
+    def test_overlap_none_treated_as_zero(self):
+        self.assertTrue(bd.uv_gate_ok(0.01, None))
+
+
 if __name__ == "__main__":
     unittest.main()