diff --git a/src/components/floor-plan/modal/auxiliary/AuxiliarySize.jsx b/src/components/floor-plan/modal/auxiliary/AuxiliarySize.jsx
index 40fb9f76..6b0abda1 100644
--- a/src/components/floor-plan/modal/auxiliary/AuxiliarySize.jsx
+++ b/src/components/floor-plan/modal/auxiliary/AuxiliarySize.jsx
@@ -84,12 +84,12 @@ export default function AuxiliarySize(props) {
 
         //1지점 선택일때는 2지점의 좌표, 2지점 선택일때는 1지점의 좌표를 조정한다.
         if (checkedRadio === 1) {
-          const newX2 = Big(x1).plus(dx.times(scaleFactor))
-          const newY2 = Big(y1).plus(dy.times(scaleFactor))
+          const newX2 = Big(x1).plus(dx.times(scaleFactor)).toNumber()
+          const newY2 = Big(y1).plus(dy.times(scaleFactor)).toNumber()
           currentObject.set({ x2: newX2, y2: newY2 })
         } else if (checkedRadio === 2) {
-          const newX1 = Big(x2).minus(dx.times(scaleFactor))
-          const newY1 = Big(y2).minus(dy.times(scaleFactor))
+          const newX1 = Big(x2).minus(dx.times(scaleFactor)).toNumber()
+          const newY1 = Big(y2).minus(dy.times(scaleFactor)).toNumber()
           currentObject.set({ x1: newX1, y1: newY1 })
         }
         //planeSize와 actualSize를 재계산한다.
diff --git a/src/hooks/module/useModule.js b/src/hooks/module/useModule.js
index c81c54cb..d4a0e7de 100644
--- a/src/hooks/module/useModule.js
+++ b/src/hooks/module/useModule.js
@@ -1,4 +1,5 @@
 import { BATCH_TYPE, POLYGON_TYPE } from '@/common/common'
+import { QPolygon } from '@/components/fabric/QPolygon'
 import { canvasState } from '@/store/canvasAtom'
 import { polygonToTurfPolygon } from '@/util/canvas-util'
 import { useRecoilValue } from 'recoil'
@@ -44,6 +45,42 @@ export function useModule() {
   const { clear: removeTrestleMaterials } = useTrestle()
   const { checkModuleDisjointSurface } = useTurf()
 
+  // clone() 대신 직접 새 QPolygon을 생성하여 Maximum call stack 방지
+  const createModuleCopy = (module, newLeft, newTop, overrides = {}) => {
+    const deltaX = newLeft - module.left
+    const deltaY = newTop - module.top
+    const newPoints = module.points.map((p) => ({
+      x: p.x + deltaX,
+      y: p.y + deltaY,
+    }))
+    return new QPolygon(newPoints, {
+      fill: module.fill,
+      stroke: module.stroke,
+      strokeWidth: module.strokeWidth,
+      opacity: module.opacity,
+      selectable: module.selectable,
+      lockMovementX: module.lockMovementX,
+      lockMovementY: module.lockMovementY,
+      lockRotation: module.lockRotation,
+      lockScalingX: module.lockScalingX,
+      lockScalingY: module.lockScalingY,
+      parentId: module.parentId,
+      initOptions: module.initOptions,
+      direction: module.direction,
+      arrow: module.arrow,
+      name: module.name,
+      surfaceId: module.surfaceId,
+      moduleInfo: module.moduleInfo,
+      left: newLeft,
+      top: newTop,
+      width: module.width,
+      height: module.height,
+      toFixed: 2,
+      sort: false,
+      ...overrides,
+    })
+  }
+
   const moduleMove = (length, direction) => {
     const selectedObj = canvas.getActiveObjects() //선택된 객체들을 가져옴
     const selectedIds = selectedObj.map((obj) => obj.id) // selectedObj의 ID 추출
@@ -256,27 +293,10 @@ export function useModule() {
 
       modules.forEach((module) => {
         const { top, left } = getPosotion(module, direction, Number(length) + Number(moduleLength) * 10, false)
-        module.clone((obj) => {
-          obj.set({
-            parentId: module.parentId,
-            initOptions: module.initOptions,
-            direction: module.direction,
-            arrow: module.arrow,
-            name: module.name,
-            type: module.type,
-            length: module.length,
-            points: module.points,
-            surfaceId: module.surfaceId,
-            moduleInfo: module.moduleInfo,
-            left,
-            top,
-            id: uuidv4(),
-          })
-          copyModule = obj
-          canvas.add(obj)
-          copyModules.push(obj)
-          obj.setCoords()
-        })
+        copyModule = createModuleCopy(module, left, top)
+        canvas.add(copyModule)
+        copyModules.push(copyModule)
+        copyModule.setCoords()
         if (isOverlapObjects(copyModule, objects) || isOutsideSurface(copyModule, surface)) {
           isWarning = true
           copyModule.set({ fill: 'red' })
@@ -318,27 +338,10 @@ export function useModule() {
     canvas.discardActiveObject() //선택해제
     modules.forEach((module) => {
       const { top, left } = getPosotion(module, direction, length, true)
-      module.clone((obj) => {
-        obj.set({
-          parentId: module.parentId,
-          initOptions: module.initOptions,
-          direction: module.direction,
-          arrow: module.arrow,
-          name: module.name,
-          type: module.type,
-          length: module.length,
-          points: module.points,
-          surfaceId: module.surfaceId,
-          moduleInfo: module.moduleInfo,
-          left,
-          top,
-          id: uuidv4(),
-        })
-        copyModules.push(obj)
-        copyModule = obj
-        canvas.add(obj)
-        canvas.renderAll()
-      })
+      copyModule = createModuleCopy(module, left, top)
+      copyModules.push(copyModule)
+      canvas.add(copyModule)
+      canvas.renderAll()
 
       if (
         isOverlapOtherModules(copyModule, otherModules) ||
@@ -412,29 +415,10 @@ export function useModule() {
 
     modules.forEach((module) => {
       const { top, left } = getPosotion(module, direction, Number(length), true)
-      module.clone((obj) => {
-        obj.set({
-          parentId: module.parentId,
-          initOptions: module.initOptions,
-          stroke: 'black',
-          direction: module.direction,
-          arrow: module.arrow,
-          name: module.name,
-          type: module.type,
-          length: module.length,
-          points: module.points,
-          moduleInfo: module.moduleInfo,
-          surfaceId: module.surfaceId,
-          left,
-          top,
-          id: uuidv4(),
-        })
-        copyModule = obj
-        canvas.add(obj)
-        copyModules.push(obj)
-        obj.setCoords()
-        console.log(obj)
-      })
+      copyModule = createModuleCopy(module, left, top, { stroke: 'black' })
+      canvas.add(copyModule)
+      copyModules.push(copyModule)
+      copyModule.setCoords()
       if (
         isOverlapOtherModules(copyModule, otherModules) ||
         isOverlapObjects(copyModule, objects) ||
@@ -770,28 +754,10 @@ export function useModule() {
     otherModules = getOtherModules(columnModules)
     columnModules.forEach((module) => {
       const { top, left } = getPosotion(module, type, moduleIntvlHor, true)
-      let copyModule = null
-      module.clone((obj) => {
-        obj.set({
-          parentId: module.parentId,
-          initOptions: module.initOptions,
-          direction: module.direction,
-          arrow: module.arrow,
-          name: module.name,
-          type: module.type,
-          length: module.length,
-          points: module.points,
-          moduleInfo: module.moduleInfo,
-          surfaceId: module.surfaceId,
-          left,
-          top,
-          id: uuidv4(),
-        })
-        copyModule = obj
-        canvas.add(obj)
-        copyModules.push(obj)
-        obj.setCoords()
-      })
+      const copyModule = createModuleCopy(module, left, top)
+      canvas.add(copyModule)
+      copyModules.push(copyModule)
+      copyModule.setCoords()
       canvas.renderAll()
 
       if (
@@ -879,29 +845,10 @@ export function useModule() {
     otherModules = getOtherModules(rowModules)
     rowModules.forEach((module) => {
       const { top, left } = getPosotion(module, type, moduleIntvlVer, true)
-      let copyModule = null
-      module.clone((obj) => {
-        obj.set({
-          parentId: module.parentId,
-          initOptions: module.initOptions,
-          direction: module.direction,
-          arrow: module.arrow,
-          name: module.name,
-          type: module.type,
-          length: module.length,
-          points: module.points,
-          surfaceId: module.surfaceId,
-          moduleInfo: module.moduleInfo,
-          fill: module.fill,
-          left,
-          top,
-          id: uuidv4(),
-        })
-        copyModule = obj
-        canvas.add(obj)
-        copyModules.push(obj)
-        obj.setCoords()
-      })
+      const copyModule = createModuleCopy(module, left, top)
+      canvas.add(copyModule)
+      copyModules.push(copyModule)
+      copyModule.setCoords()
       canvas.renderAll()
 
       if (
diff --git a/src/hooks/module/useModuleBasicSetting.js b/src/hooks/module/useModuleBasicSetting.js
index 365ed1b0..c48c2d21 100644
--- a/src/hooks/module/useModuleBasicSetting.js
+++ b/src/hooks/module/useModuleBasicSetting.js
@@ -184,14 +184,14 @@ export function useModuleBasicSetting(tabNum) {
 
     // 방향에 따른 좌표 설정
     const directionConfig = {
-      south: { coord1: 'y1', coord2: 'y2', findExtreme: Math.max },
-      north: { coord1: 'y1', coord2: 'y2', findExtreme: Math.min },
-      east: { coord1: 'x1', coord2: 'x2', findExtreme: Math.max },
-      west: { coord1: 'x1', coord2: 'x2', findExtreme: Math.min },
+      south: { coord1: 'y1', coord2: 'y2', findExtreme: Math.max, offsetX: 0, offsetY: 1 },
+      north: { coord1: 'y1', coord2: 'y2', findExtreme: Math.min, offsetX: 0, offsetY: -1 },
+      east: { coord1: 'x1', coord2: 'x2', findExtreme: Math.max, offsetX: 1, offsetY: 0 },
+      west: { coord1: 'x1', coord2: 'x2', findExtreme: Math.min, offsetX: -1, offsetY: 0 },
     }
 
     const config = directionConfig[direction] || directionConfig.south
-    const { coord1, coord2, findExtreme } = config
+    const { coord1, coord2, offsetX, offsetY } = config
 
     // 2. 직선만 필터링 (대각선 제외)
     // 남/북: y1 === y2 인 경우 수평 직선
@@ -200,22 +200,29 @@ export function useModuleBasicSetting(tabNum) {
 
     if (straightLines.length === 0) return
 
-    // 3. 가장 끝에 있는 직선 찾기
-    // 남쪽: 가장 하단 (y값이 가장 큰), 북쪽: 가장 상단 (y값이 가장 작은)
-    // 동쪽: 가장 오른쪽 (x값이 가장 큰), 서쪽: 가장 왼쪽 (x값이 가장 작은)
-    const extremeValue = findExtreme(...straightLines.map((line) => line[coord1]))
-    const eavesLines = straightLines.filter((line) => line[coord1] === extremeValue)
+    // 3. 폴리곤의 turf polygon 생성 (처마 방향 판별용)
+    const points = polygon.getCurrentPoints()
+    const turfCoords = points.map((p) => [p.x, p.y])
+    turfCoords.push(turfCoords[0]) // 폴리곤 닫기
+    const turfPolygon = turf.polygon([turfCoords])
 
-    // 4. 직선에 대해 타입 설정
+    // 4. 각 직선에 대해 처마/용마루 판별
+    // 라인 중점에서 처마 방향으로 약간 이동한 점이 폴리곤 외부이면 처마(eaves)
+    // 폴리곤 내부이면 용마루(ridge)
     straightLines.forEach((line) => {
-      if (eavesLines.includes(line)) {
-        // 가장 끝에 있는 직선은 eaves
+      const midX = (line.x1 + line.x2) / 2
+      const midY = (line.y1 + line.y2) / 2
+      // 처마 방향으로 약간 이동한 테스트 포인트
+      const testPoint = turf.point([midX + offsetX * 0.5, midY + offsetY * 0.5])
+
+      if (!turf.booleanPointInPolygon(testPoint, turfPolygon)) {
+        // 테스트 포인트가 폴리곤 외부 → 처마 방향을 향함
         line.attributes = {
           ...line.attributes,
           type: LINE_TYPE.WALLLINE.EAVES,
         }
       } else {
-        // 나머지 직선은 ridge
+        // 테스트 포인트가 폴리곤 내부 → 용마루 방향을 향함
         line.attributes = {
           ...line.attributes,
           type: LINE_TYPE.SUBLINE.RIDGE,
diff --git a/src/hooks/surface/useSurfaceShapeBatch.js b/src/hooks/surface/useSurfaceShapeBatch.js
index d7df9b6d..27a6f737 100644
--- a/src/hooks/surface/useSurfaceShapeBatch.js
+++ b/src/hooks/surface/useSurfaceShapeBatch.js
@@ -208,6 +208,13 @@ export function useSurfaceShapeBatch({ isHidden, setIsHidden }) {
           isXInversion: xInversion,
           isYInversion: yInversion,
         })
+        // 최초 생성 시 planeSize를 계산된 길이로 저장 (회전 후 좌표 반올림에 의한 오차 방지)
+        batchSurface.lines.forEach((line) => {
+          if (!line.attributes.planeSize || line.attributes.planeSize === 0) {
+            line.attributes.planeSize = line.getLength()
+          }
+        })
+
         canvas.setActiveObject(batchSurface)
         setSurfaceShapePattern(batchSurface, roofDisplay.column)
         drawDirectionArrow(batchSurface)
@@ -375,9 +382,9 @@ export function useSurfaceShapeBatch({ isHidden, setIsHidden }) {
         }
 
         points = [
-          { x: pointer.x, y: pointer.y - parseInt(newLength2) / 2 },
-          { x: pointer.x - parseInt(length1) / 2, y: pointer.y + parseInt(newLength2) / 2 },
-          { x: pointer.x + parseInt(length1) / 2, y: pointer.y + parseInt(newLength2) / 2 },
+          { x: pointer.x, y: pointer.y - newLength2 / 2 },
+          { x: pointer.x - length1 / 2, y: pointer.y + newLength2 / 2 },
+          { x: pointer.x + length1 / 2, y: pointer.y + newLength2 / 2 },
         ]
 
         break
diff --git a/src/hooks/usePolygon.js b/src/hooks/usePolygon.js
index 40a3d85f..3a83c947 100644
--- a/src/hooks/usePolygon.js
+++ b/src/hooks/usePolygon.js
@@ -1023,6 +1023,9 @@ export const usePolygon = () => {
       const line = divideLines[i]
       const { intersections, startPoint, endPoint } = line
 
+      // 원본 라인의 기하학적 길이 (비율 계산용)
+      const originalGeomLength = Math.round(Math.hypot(line.x2 - line.x1, line.y2 - line.y1)) * 10
+
       if (intersections.length === 1) {
         const newLinePoint1 = [line.x1, line.y1, intersections[0].x, intersections[0].y]
         const newLinePoint2 = [intersections[0].x, intersections[0].y, line.x2, line.y2]
@@ -1042,25 +1045,43 @@ export const usePolygon = () => {
           name: 'newLine',
         })
 
-        // 두 라인 중 큰 길이로 통일
+        // 분할된 각 세그먼트의 기하학적 길이
         const length1 = Math.round(Math.hypot(newLine1.x1 - newLine1.x2, newLine1.y1 - newLine1.y2)) * 10
         const length2 = Math.round(Math.hypot(newLine2.x1 - newLine2.x2, newLine2.y1 - newLine2.y2)) * 10
-        const maxLength = Math.max(length1, length2)
-        const unifiedPlaneSize = line.attributes.planeSize ?? maxLength
-        const unifiedActualSize = line.attributes.actualSize ?? maxLength
+
+        // 원본에 planeSize/actualSize가 있으면 비율로 분배, 없으면 기하학적 길이 사용
+        let planeSize1, planeSize2, actualSize1, actualSize2
+        if (line.attributes.planeSize && originalGeomLength > 0) {
+          const ratio1 = length1 / originalGeomLength
+          const ratio2 = length2 / originalGeomLength
+          planeSize1 = Math.round(line.attributes.planeSize * ratio1)
+          planeSize2 = Math.round(line.attributes.planeSize * ratio2)
+        } else {
+          planeSize1 = length1
+          planeSize2 = length2
+        }
+        if (line.attributes.actualSize && originalGeomLength > 0) {
+          const ratio1 = length1 / originalGeomLength
+          const ratio2 = length2 / originalGeomLength
+          actualSize1 = Math.round(line.attributes.actualSize * ratio1)
+          actualSize2 = Math.round(line.attributes.actualSize * ratio2)
+        } else {
+          actualSize1 = length1
+          actualSize2 = length2
+        }
 
         newLine1.attributes = {
           ...line.attributes,
-          planeSize: unifiedPlaneSize,
-          actualSize: unifiedActualSize,
+          planeSize: planeSize1,
+          actualSize: actualSize1,
         }
-        newLine1.length = maxLength
+        newLine1.length = length1
         newLine2.attributes = {
           ...line.attributes,
-          planeSize: unifiedPlaneSize,
-          actualSize: unifiedActualSize,
+          planeSize: planeSize2,
+          actualSize: actualSize2,
         }
-        newLine2.length = maxLength
+        newLine2.length = length2
 
         newLines.push(newLine1, newLine2)
         divideLines.splice(i, 1) // 기존 line 제거
@@ -1080,12 +1101,25 @@ export const usePolygon = () => {
           })
 
           const calcLength = Math.round(Math.hypot(newLine.x1 - newLine.x2, newLine.y1 - newLine.y2)) * 10
+
+          let segPlaneSize, segActualSize
+          if (line.attributes.planeSize && originalGeomLength > 0) {
+            segPlaneSize = Math.round(line.attributes.planeSize * (calcLength / originalGeomLength))
+          } else {
+            segPlaneSize = calcLength
+          }
+          if (line.attributes.actualSize && originalGeomLength > 0) {
+            segActualSize = Math.round(line.attributes.actualSize * (calcLength / originalGeomLength))
+          } else {
+            segActualSize = calcLength
+          }
+
           newLine.attributes = {
             ...line.attributes,
-            planeSize: line.attributes.planeSize ?? calcLength,
-            actualSize: line.attributes.actualSize ?? calcLength,
+            planeSize: segPlaneSize,
+            actualSize: segActualSize,
           }
-          newLine.length = line.attributes.planeSize ?? calcLength
+          newLine.length = calcLength
 
           newLines.push(newLine)
           currentPoint = minDistancePoint
@@ -1100,12 +1134,25 @@ export const usePolygon = () => {
           name: 'newLine',
         })
         const lastCalcLength = Math.round(Math.hypot(newLine.x1 - newLine.x2, newLine.y1 - newLine.y2)) * 10
+
+        let lastPlaneSize, lastActualSize
+        if (line.attributes.planeSize && originalGeomLength > 0) {
+          lastPlaneSize = Math.round(line.attributes.planeSize * (lastCalcLength / originalGeomLength))
+        } else {
+          lastPlaneSize = lastCalcLength
+        }
+        if (line.attributes.actualSize && originalGeomLength > 0) {
+          lastActualSize = Math.round(line.attributes.actualSize * (lastCalcLength / originalGeomLength))
+        } else {
+          lastActualSize = lastCalcLength
+        }
+
         newLine.attributes = {
           ...line.attributes,
-          planeSize: line.attributes.planeSize ?? lastCalcLength,
-          actualSize: line.attributes.actualSize ?? lastCalcLength,
+          planeSize: lastPlaneSize,
+          actualSize: lastActualSize,
         }
-        newLine.length = line.attributes.planeSize ?? lastCalcLength
+        newLine.length = lastCalcLength
 
         newLines.push(newLine)
         divideLines.splice(i, 1) // 기존 line 제거