diff --git a/Tools/ModelTranslator/qr_bridge.py b/Tools/ModelTranslator/qr_bridge.py
index f20c173a..48503d7f 100644
--- a/Tools/ModelTranslator/qr_bridge.py
+++ b/Tools/ModelTranslator/qr_bridge.py
@@ -4,6 +4,9 @@ import glob
 import os
 
 QR_TIMEOUT = 120.0   # 引擎轮询超时（秒）
+QR_INPUT_CAP = 50000        # quad 后端 QR 前预 collapse 的中等密度目标面数
+QR_HOLE_MAX_SIDES = 6       # 补洞上限边数：只补 <=6 边的薄部位小洞
+QR_CATASTROPHIC_TOL = 12    # 软水密门容忍：补洞后仍多出超此数的开边/非流形才判灾难性
 
 
 def find_qr_engine():
@@ -65,8 +68,14 @@ def parse_progress(text):
 
 
 def topology_acceptable(src_boundary, src_nonmanifold,
-                        out_boundary, out_nonmanifold):
-    """QR 输出拓扑是否可接受：不比输入引入更多开边(孔洞)/非流形边。
-    QR 引擎在激进减面下会非确定性地打出孔洞——封闭输入(0/0)时要求输出也 0/0，
-    输入本身开放(壳)时按其基线放行；否则判破损，交上层回退 collapse。"""
-    return out_boundary <= src_boundary and out_nonmanifold <= src_nonmanifold
+                        out_boundary, out_nonmanifold, tol=0):
+    """QR 输出拓扑是否可接受：不比输入多出超过 tol 的开边(孔洞)/非流形边。
+    tol=0（默认）为零容忍严格门；quad 后端补小洞后用 tol=QR_CATASTROPHIC_TOL 只挡灾难性破损。"""
+    return (out_boundary <= src_boundary + tol
+            and out_nonmanifold <= src_nonmanifold + tol)
+
+
+def precollapse_target(face_count, cap=QR_INPUT_CAP):
+    """QR 前预 collapse 目标：面数 > cap 返回 cap（先减到中等密度），否则 None（跳过）。
+    高密度网格直接 QR 必破洞，先 collapse 到中等密度给 QR 一个稳定输入。"""
+    return cap if face_count > cap else None
diff --git a/Tools/ModelTranslator/tests/test_qr_bridge.py b/Tools/ModelTranslator/tests/test_qr_bridge.py
index 97155762..71c7d7fc 100644
--- a/Tools/ModelTranslator/tests/test_qr_bridge.py
+++ b/Tools/ModelTranslator/tests/test_qr_bridge.py
@@ -141,5 +141,38 @@ class TestTopologyAcceptable(unittest.TestCase):
         self.assertTrue(qb.topology_acceptable(10, 2, 8, 1))
 
 
+class TestTopologyTolerance(unittest.TestCase):
+    def test_tol_allows_small_increase(self):
+        # 封闭输入 + QR 多出 3 开边，容忍 12 内 -> 接受
+        self.assertTrue(qb.topology_acceptable(0, 0, 3, 0, tol=12))
+
+    def test_tol_rejects_large_increase(self):
+        self.assertFalse(qb.topology_acceptable(0, 0, 13, 0, tol=12))
+
+    def test_tol_applies_to_nonmanifold(self):
+        self.assertTrue(qb.topology_acceptable(0, 0, 0, 12, tol=12))
+        self.assertFalse(qb.topology_acceptable(0, 0, 0, 13, tol=12))
+
+    def test_default_tol_zero_strict(self):
+        # 默认 tol=0：现有严格语义不变
+        self.assertFalse(qb.topology_acceptable(0, 0, 1, 0))
+        self.assertTrue(qb.topology_acceptable(0, 0, 0, 0))
+
+
+class TestPrecollapseTarget(unittest.TestCase):
+    def test_above_cap_returns_cap(self):
+        self.assertEqual(qb.precollapse_target(1000000, 50000), 50000)
+
+    def test_below_cap_returns_none(self):
+        self.assertIsNone(qb.precollapse_target(40000, 50000))
+
+    def test_at_cap_returns_none(self):
+        self.assertIsNone(qb.precollapse_target(50000, 50000))
+
+    def test_default_cap(self):
+        self.assertEqual(qb.precollapse_target(60000), qb.QR_INPUT_CAP)
+        self.assertIsNone(qb.precollapse_target(40000))
+
+
 if __name__ == "__main__":
     unittest.main()