diff --git a/src/hooks/usePolygon.js b/src/hooks/usePolygon.js
index b66996cb..21429d66 100644
--- a/src/hooks/usePolygon.js
+++ b/src/hooks/usePolygon.js
@@ -765,6 +765,14 @@ export const usePolygon = () => {
   const splitPolygonWithLines = (polygon) => {
     polygon.set({ visible: false })
 
+    const auxiliaryLines = canvas
+      .getObjects()
+      .filter((obj) => obj.name === 'auxiliaryLine' && polygon.inPolygonImproved(obj.startPoint) && polygon.inPolygonImproved(obj.endPoint))
+
+    auxiliaryLines.forEach((auxiliaryLine) => {
+      polygon.innerLines.push(auxiliaryLine)
+    })
+
     let innerLines = [...polygon.innerLines].filter((line) => line.visible)
 
     /*// innerLine이 세팅이 안되어있는경우 찾아서 세팅한다.
@@ -845,6 +853,7 @@ export const usePolygon = () => {
           if (polygonLine.attributes?.type && innerLine.attributes) {
             polygonLine.need = false
             innerLine.attributes.type = polygonLine.attributes.type
+            innerLine.attributes.isStart = true
           }
         }
       })
@@ -1025,6 +1034,10 @@ export const usePolygon = () => {
 
     polygonLines = [...polygonLines, ...newLines]
 
+    polygonLines.forEach((polygonLine) => {
+      polygonLine.attributes = { ...polygonLine.attributes, isStart: true }
+    })
+
     let allLines = [...polygonLines, ...innerLines]
 
     /*allLines.forEach((line) => {
@@ -1058,16 +1071,6 @@ export const usePolygon = () => {
       allPoints.push(endPoint)
     })
 
-    // allPoints에서 중복을 제거한다.
-    const uniquePoints = allPoints.filter((point, index, self) => {
-      return (
-        index ===
-        self.findIndex((p) => {
-          return isSamePoint(p, point)
-        })
-      )
-    })
-
     // 2025-02-19 대각선은 케라바, 직선은 용마루로 세팅
     innerLines.forEach((innerLine) => {
       const startPoint = innerLine.startPoint
@@ -1268,7 +1271,6 @@ export const usePolygon = () => {
     })
 
     //지붕 완료 후 보조선을 전부 제거한다.
-    const auxiliaryLines = canvas.getObjects().filter((obj) => obj.name === 'auxiliaryLine')
 
     auxiliaryLines.forEach((line) => {
       canvas.remove(line)
@@ -1393,6 +1395,20 @@ export const usePolygon = () => {
 
     // 최종 함수
     function getPath(start, end, graph, epsilon = 1) {
+      // startPoint와 arrivalPoint가 될 수 있는 점은 line.attributes.type이 'default' 혹은 null이 아닌 line인 경우에만 가능
+      const isValidPoint = (point) => {
+        return allLines.some((line) => {
+          const isOnLine = isSamePoint(line.startPoint, point, epsilon) || isSamePoint(line.endPoint, point, epsilon)
+          const hasValidType = line.attributes?.type && line.attributes.type !== 'default'
+          return isOnLine && hasValidType
+        })
+      }
+
+      if (!isValidPoint(start) || !isValidPoint(end)) {
+        console.log('시작점 또는 도착점이 유효하지 않음. 무시.')
+        return []
+      }
+
       if (isDirectlyConnected(start, end, graph, epsilon)) {
         console.log('직선 연결 있음. 무시.')
         return []
@@ -1404,36 +1420,62 @@ export const usePolygon = () => {
         return []
       }
 
+      // 사용된 노드들을 graph에서 제거
+      if (path.length > 0) {
+        path.forEach((point) => {
+          const pointKey = pointToKey(point, epsilon)
+          delete graph[pointKey]
+          // 다른 노드들의 연결에서도 이 노드를 제거
+          Object.keys(graph).forEach((key) => {
+            graph[key] = graph[key].filter((neighbor) => !isSamePoint(neighbor.point, point, epsilon))
+          })
+        })
+      }
+
       return path
     }
 
     const roofs = []
+    const remainingLines = [...allLines] // 사용 가능한 line들의 복사본
 
-    allLines.forEach((line) => {
-      // 그래프 생성
+    // isStart가 true인 line들만 시작점으로 사용
+    const startLines = remainingLines.filter(line => line.attributes?.isStart === true)
+    
+    startLines.forEach((startLine) => {
+      // 현재 남아있는 line들로 그래프 생성
       const graph = {}
-      const edges = allLines
-        .filter((line2) => line !== line2)
-        .map((line) => {
-          return [line.startPoint, line.endPoint]
-        })
 
-      for (const [p1, p2] of edges) {
+      for (const line of remainingLines.filter((line2) => line2 !== startLine)) {
+        const p1 = line.startPoint
+        const p2 = line.endPoint
         const key1 = pointToKey(p1)
         const key2 = pointToKey(p2)
         const distance = calcDistance(p1, p2)
+        const isStartLine = line.attributes?.isStart === true
 
         if (!graph[key1]) graph[key1] = []
         if (!graph[key2]) graph[key2] = []
 
-        graph[key1].push({ point: p2, distance })
-        graph[key2].push({ point: p1, distance })
+        // isStart가 아닌 line을 우선하도록 distance 조정
+        const adjustedDistance = isStartLine ? distance + 1000 : distance
+
+        graph[key1].push({ point: p2, distance: adjustedDistance, line })
+        graph[key2].push({ point: p1, distance: adjustedDistance, line })
       }
 
-      const startPoint = { ...line.startPoint } // 시작점
-
-      let arrivalPoint = { ...line.endPoint } // 도착점
-      roofs.push(getPath(startPoint, arrivalPoint, graph))
+      const startPoint = { ...startLine.startPoint } // 시작점
+      let arrivalPoint = { ...startLine.endPoint } // 도착점
+      
+      const roof = getPath(startPoint, arrivalPoint, graph)
+      if (roof.length > 0) {
+        roofs.push(roof)
+        
+        // 사용된 startLine을 remainingLines에서 제거
+        const startLineIndex = remainingLines.findIndex(line => line === startLine)
+        if (startLineIndex !== -1) {
+          remainingLines.splice(startLineIndex, 1)
+        }
+      }
     })
 
     return removeDuplicatePolygons(
diff --git a/src/util/canvas-util.js b/src/util/canvas-util.js
index 166b7acb..d012f837 100644
--- a/src/util/canvas-util.js
+++ b/src/util/canvas-util.js
@@ -378,7 +378,7 @@ export const calculateIntersection = (line1, line2) => {
 export const getInterSectionLineNotOverCoordinate = (line1, line2) => {
   const result = intersect([line1.x1, line1.y1], [line1.x2, line1.y2], [line2.x1, line2.y1], [line2.x2, line2.y2])
   if (result) {
-    return { x: Math.round(result[0]), y: Math.round(result[1]) }
+    return { x: result[0], y: result[1] }
   }
   return null
 }