diff --git a/Cad/DrawingStyleManager.cs b/Cad/DrawingStyleManager.cs
index 28f3aa3..2cb271b 100644
--- a/Cad/DrawingStyleManager.cs
+++ b/Cad/DrawingStyleManager.cs
@@ -10,6 +10,7 @@ namespace CadParamPluging.Cad
             OutlineBold,
             OutlineThin,
             PartContour,
+            BreakLine,      // 截断线（白色双点划线）
             Centerline,
             Hidden,
             Hatch,
@@ -57,7 +58,9 @@ namespace CadParamPluging.Cad
                 case Role.OutlineBold:
                     return new LayerSpec { LayerName = "粗实线", DefaultLinetypeName = "Continuous", DefaultLineWeight = LineWeight.LineWeight050, DefaultColorIndex = 7 };
                 case Role.PartContour:
-                    return new LayerSpec { LayerName = "双点划线", DefaultLinetypeName = "PHANTOM", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 7 };
+                    return new LayerSpec { LayerName = "双点划线", DefaultLinetypeName = "PHANTOM", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 2 };
+                case Role.BreakLine:
+                    return new LayerSpec { LayerName = "截断线", DefaultLinetypeName = "PHANTOM", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 7 };
                 case Role.Centerline:
                     return new LayerSpec { LayerName = "中心线", DefaultLinetypeName = "CENTER", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 7 };
                 case Role.Hidden:
diff --git a/Cad/FeatureDrivenDrawer.cs b/Cad/FeatureDrivenDrawer.cs
index eaa3f3f..7df0b46 100644
--- a/Cad/FeatureDrivenDrawer.cs
+++ b/Cad/FeatureDrivenDrawer.cs
@@ -601,17 +601,18 @@ namespace CadParamPluging.Cad
         }
 
         /// <summary>
-        /// 轧制：绘制对称轴（垂直中心线）
+        /// 轧制：绘制截断线（两根双点划线，间距5mm）
         /// </summary>
         private static void DrawRingSymmetryAxis(DrawingContext ctx, double ox, double oy, double height)
         {
-            const double extend = 5.0;       // 中心线在轮廓上下各延长一点（与其它中心线的延长量保持一致）
+            const double extend = 5.0;       // 截断线在轮廓上下各延长一点
             const double frameMargin = 5.0;  // 避免越过图框边界
+            const double lineSpacing = 5.0;  // 两根截断线间距5mm
 
             var y0 = oy - extend;
             var y1 = oy + height + extend;
 
-            // 若能检测到白色外框，则把中心线端点夹在图框内（留出少量安全边距）。
+            // 若能检测到白色外框，则把截断线端点夹在图框内（留出少量安全边距）。
             try
             {
                 var frameExtents = TemplateDrawingService.ComputeWhiteFrameExtents(ctx?.Ctx);
@@ -634,10 +635,18 @@ namespace CadParamPluging.Cad
                 y1 = oy + height;
             }
 
-            var line = new Line(new Point3d(ox, y0, 0), new Point3d(ox, y1, 0));
-            ctx.Style?.Apply(line, DrawingStyleManager.Role.Centerline);
-            ctx.Btr.AppendEntity(line);
-            ctx.Tr.AddNewlyCreatedDBObject(line, true);
+            // 绘制两根双点划线，间距 lineSpacing
+            // 第一根在 ox 位置
+            var line1 = new Line(new Point3d(ox, y0, 0), new Point3d(ox, y1, 0));
+            ctx.Style?.Apply(line1, DrawingStyleManager.Role.BreakLine);  // 使用截断线样式（白色双点划线）
+            ctx.Btr.AppendEntity(line1);
+            ctx.Tr.AddNewlyCreatedDBObject(line1, true);
+
+            // 第二根在 ox - lineSpacing 位置
+            var line2 = new Line(new Point3d(ox - lineSpacing, y0, 0), new Point3d(ox - lineSpacing, y1, 0));
+            ctx.Style?.Apply(line2, DrawingStyleManager.Role.BreakLine);  // 使用截断线样式（白色双点划线）
+            ctx.Btr.AppendEntity(line2);
+            ctx.Tr.AddNewlyCreatedDBObject(line2, true);
         }
 
         /// <summary>
@@ -781,7 +790,7 @@ namespace CadParamPluging.Cad
         }
 
         /// <summary>
-        /// 轧制：零件轮廓（右半边）
+        /// 轧制：零件轮廓（闭合方框，双点划线黄色）
         /// </summary>
         private static void DrawPartContourHalf(DrawingContext ctx, double ox, double oy, double forgingHeight,
             double outerDiaPrime, double? innerDiaPrime, double heightPrime)
@@ -793,28 +802,16 @@ namespace CadParamPluging.Cad
             var offsetY = (forgingHeight - h) / 2.0;
             var y0 = oy + offsetY;
 
-            // 右半边零件轮廓（开口）
+            // 绘制闭合方框（仅画外轮廓，不画内径线）
             var polyPart = new Polyline();
             polyPart.AddVertexAt(0, new Point2d(ox, y0), 0, 0, 0);
             polyPart.AddVertexAt(1, new Point2d(ox + Rp, y0), 0, 0, 0);
             polyPart.AddVertexAt(2, new Point2d(ox + Rp, y0 + h), 0, 0, 0);
             polyPart.AddVertexAt(3, new Point2d(ox, y0 + h), 0, 0, 0);
-            polyPart.Closed = false;  // 不闭合
+            polyPart.Closed = true;  // 闭合方框
             ctx.Style?.Apply(polyPart, DrawingStyleManager.Role.PartContour);
             ctx.Btr.AppendEntity(polyPart);
             ctx.Tr.AddNewlyCreatedDBObject(polyPart, true);
-
-            // 右侧内径轮廓
-            if (innerDiaPrime.HasValue && innerDiaPrime.Value > 0 && innerDiaPrime.Value < outerDiaPrime)
-            {
-                var xiR = ox + innerDiaPrime.Value / 2.0;
-                var yTop = y0 + h;
-
-                var lineInner = new Line(new Point3d(xiR, y0, 0), new Point3d(xiR, yTop, 0));
-                ctx.Style?.Apply(lineInner, DrawingStyleManager.Role.PartContour);
-                ctx.Btr.AppendEntity(lineInner);
-                ctx.Tr.AddNewlyCreatedDBObject(lineInner, true);
-            }
         }
 
         #endregion