diff --git a/Cad/BlockRawFreeForgeRoundHeadDrawer.cs b/Cad/BlockRawFreeForgeRoundHeadDrawer.cs
index bb8efd1..3ccfe8b 100644
--- a/Cad/BlockRawFreeForgeRoundHeadDrawer.cs
+++ b/Cad/BlockRawFreeForgeRoundHeadDrawer.cs
@@ -100,10 +100,6 @@ namespace CadParamPluging.Cad
                 ? innerFilletParam.Value 
                 : 0;
 
-            // 1. 绘制完整锻件外轮廓（方体有圆头 - 白色，大圆弧）
-            // 修正：圆弧弦线需向内缩进 headFilletR (原 logic 使用 innerFilletR)，以与锻件外侧圆角起点对齐
-            DrawBlockRoundHeadOutline(ctx, ox, oy, visualTotalW, H, arcHeight, headFilletR);
-
             // 2. 绘制分段式内框（左、中、右三段）以支持中间剖面区域的独立圆角
             // 中间区域（剖面）作为主体，如果设置了圆角，四个角都应为圆角
             
@@ -139,15 +135,27 @@ namespace CadParamPluging.Cad
             // 使用 sectionFilletR
             DrawBoxSectionContourWithFillet(ctx, xSectionLeft, xSectionRight, oy, H, sectionFilletR);
 
+            // Calculate effective head fillet R (clamped by side frame width) to ensure Outline matches SideFrame
+            double sideFrameWidth = xSectionLeft - xInnerLeft;
+            double maxR = Math.Min(sideFrameWidth * 0.5, H * 0.5);
+            double effectiveHeadR = Math.Min(headFilletR, maxR);
+
             // 绘制左侧框线（连接左端圆弧和中间剖面框）
             // 左端: xInnerLeft (需处理左上下角的圆角 - 使用 headFilletR)
             // 右端: xSectionLeft (连接到中间框的直边)
-            DrawBoxSideFrame(ctx, xInnerLeft, xSectionLeft, oy, H, headFilletR, isLeft: true);
+            // Note: Extend horizontally by sectionFilletR to achieve "Horizontal Closure" with the section fillet
+            DrawBoxSideFrame(ctx, xInnerLeft, xSectionLeft + sectionFilletR, oy, H, headFilletR, isLeft: true);
 
             // 绘制右侧框线
             // 左端: xSectionRight (连接到中间框的直边)
             // 右端: xInnerRight (需处理右上下角的圆角 - 使用 headFilletR)
-            DrawBoxSideFrame(ctx, xSectionRight, xInnerRight, oy, H, headFilletR, isLeft: false);
+            // Note: Extend horizontally inwards by sectionFilletR
+            DrawBoxSideFrame(ctx, xSectionRight - sectionFilletR, xInnerRight, oy, H, headFilletR, isLeft: false);
+
+            // 1. 绘制完整锻件外轮廓（方体有圆头 - 白色，大圆弧）
+            // 修正：圆弧弦线需向内缩进 effectiveHeadR (Clamped)，以与锻件外侧圆角起点对齐
+            // This ensures the Big Arc starts curving exactly where the Side Frame vertical edge ends.
+            DrawBlockRoundHeadOutline(ctx, ox, oy, visualTotalW, H, arcHeight, effectiveHeadR);
 
             // 3. 剖面填充 - 只在中间区域
             // 使用 sectionFilletR
@@ -315,10 +323,13 @@ namespace CadParamPluging.Cad
                 double xInnerLeft = ox + arcHeight;
                 double xInnerRight = ox + totalWidth - arcHeight;
                 
-                double yBottomStraight = oy + r;
-                double yTopStraight = oy + H - r;
+                // 修正：为了确保视觉上与圆角完全闭合，稍微向圆角区域延伸一点 (0.8 * r)
+                // 用户的需求是“再高一点和低一点”，这意味着需要一定的重叠量来消除缝隙
+                double overlapFactor = 0.8; 
+                double yBottomStraight = oy + r * overlapFactor;
+                double yTopStraight = oy + H - r * overlapFactor;
                 
-                double chordLength = H - 2.0 * r;
+                double chordLength = yTopStraight - yBottomStraight;
                 if (chordLength < 0.1) return; // Should not happen for reasonable params
 
                 double sagitta = arcHeight;
@@ -421,12 +432,6 @@ namespace CadParamPluging.Cad
                    poly.AddVertexAt(4, new Point2d(xStart + r, yTop), 0, 0, 0);
                    poly.AddVertexAt(5, new Point2d(xEnd, yTop), 0, 0, 0);
                 }
-                else
-                {
-                   poly.AddVertexAt(1, new Point2d(xStart, yBottom), 0, 0, 0);
-                   poly.AddVertexAt(2, new Point2d(xStart, yTop), 0, 0, 0);
-                   poly.AddVertexAt(3, new Point2d(xEnd, yTop), 0, 0, 0);
-                }
                 poly.Closed = false;
             }
             else