diff --git a/src/components/fabric/QPolygon.js b/src/components/fabric/QPolygon.js
index 7c52a0ad..0022b820 100644
--- a/src/components/fabric/QPolygon.js
+++ b/src/components/fabric/QPolygon.js
@@ -268,64 +268,70 @@ export const QPolygon = fabric.util.createClass(fabric.Polygon, {
         break
     }
 
-    const types = []
-    this.lines.forEach((line) => types.push(line.attributes.type))
+    const types = this.lines.map((line) => line.attributes.type)
 
-    const gableType = [LINE_TYPE.WALLLINE.GABLE, LINE_TYPE.WALLLINE.JERKINHEAD]
-    const isEaves = types.every((type) => type === LINE_TYPE.WALLLINE.EAVES)
-
-    let isGable = false
-    if (types.includes(LINE_TYPE.WALLLINE.GABLE)) {
-      const gableOdd = types.filter((type, i) => i % 2 === 0)
-      const gableEven = types.filter((type, i) => i % 2 === 1)
-      if (
-        (gableOdd.every((type) => type === LINE_TYPE.WALLLINE.EAVES) && gableEven.every((type) => gableType.includes(type))) ||
-        (gableEven.every((type) => type === LINE_TYPE.WALLLINE.EAVES) && gableOdd.every((type) => gableType.includes(type)))
-      ) {
-        isGable = true
+    const isGableRoof = function (types) {
+      if (!types.includes(LINE_TYPE.WALLLINE.GABLE)) {
+        return false
       }
+      const gableTypes = [LINE_TYPE.WALLLINE.GABLE, LINE_TYPE.WALLLINE.JERKINHEAD]
+      const oddTypes = types.filter((type, i) => i % 2 === 0)
+      const evenTypes = types.filter((type, i) => i % 2 === 1)
+
+      const oddAllEaves = oddTypes.every((type) => type === LINE_TYPE.WALLLINE.EAVES)
+      const evenAllGable = evenTypes.every((type) => gableTypes.includes(type))
+      const evenAllEaves = evenTypes.every((type) => type === LINE_TYPE.WALLLINE.EAVES)
+      const oddAllGable = oddTypes.every((type) => gableTypes.includes(type))
+
+      return (oddAllEaves && evenAllGable) || (evenAllEaves && oddAllGable)
     }
 
-    let isShed = false
-    if (types.includes(LINE_TYPE.WALLLINE.SHED)) {
-      const sheds = this.lines.filter((line) => line.attributes !== undefined && line.attributes.type === LINE_TYPE.WALLLINE.SHED)
-      const areLinesParallel = function (line1, line2) {
-        const angle1 = calculateAngle(line1.startPoint, line1.endPoint)
-        const angle2 = calculateAngle(line2.startPoint, line2.endPoint)
-        return angle1 === angle2
+    const isShedRoof = function (types, lines) {
+      const gableTypes = [LINE_TYPE.WALLLINE.GABLE, LINE_TYPE.WALLLINE.JERKINHEAD]
+      if (!types.includes(LINE_TYPE.WALLLINE.SHED)) {
+        return false
+      }
+      const shedLines = lines.filter((line) => line.attributes?.type === LINE_TYPE.WALLLINE.SHED)
+      const areShedLinesParallel = function (shedLines) {
+        return shedLines.every((shed, i) => {
+          const nextShed = shedLines[(i + 1) % shedLines.length]
+          const angle1 = calculateAngle(shed.startPoint, shed.endPoint)
+          const angle2 = calculateAngle(nextShed.startPoint, nextShed.endPoint)
+          return angle1 === angle2
+        })
+      }
+      if (!areShedLinesParallel(shedLines)) {
+        return false
       }
-      let isShedRoof = true
-      sheds.forEach((shed, i) => {
-        isShedRoof = areLinesParallel(shed, sheds[(i + 1) % sheds.length])
-      })
 
-      if (isShedRoof) {
-        const eaves = this.lines
-          .filter((line) => line.attributes !== undefined && line.attributes.type === LINE_TYPE.WALLLINE.EAVES)
-          .filter((line) => {
-            const angle1 = calculateAngle(sheds[0].startPoint, sheds[0].endPoint)
-            const angle2 = calculateAngle(line.startPoint, line.endPoint)
-            if (Math.abs(angle1 - angle2) === 180) {
-              return line
-            }
-          })
-        if (eaves.length > 0) {
-          const gables = this.lines.filter((line) => sheds.includes(line) === false && eaves.includes(line) === false)
-          const isGable = gables.every((line) => gableType.includes(line.attributes.type))
-          if (isGable) {
-            isShed = true
-          }
-        }
+      const getParallelEavesLines = function (shedLines, lines) {
+        const eavesLines = lines.filter((line) => line.attributes?.type === LINE_TYPE.WALLLINE.EAVES)
+
+        const referenceAngle = calculateAngle(shedLines[0].startPoint, shedLines[0].endPoint)
+
+        return eavesLines.filter((line) => {
+          const eavesAngle = calculateAngle(line.startPoint, line.endPoint)
+          return Math.abs(referenceAngle - eavesAngle) === 180
+        })
       }
+
+      const parallelEaves = getParallelEavesLines(shedLines, lines)
+      if (parallelEaves.length === 0) {
+        return false
+      }
+
+      const remainingLines = lines.filter((line) => !shedLines.includes(line) && !parallelEaves.includes(line))
+      return remainingLines.every((line) => gableTypes.includes(line.attributes.type))
     }
 
-    if (isEaves) {
+    if (types.every((type) => type === LINE_TYPE.WALLLINE.EAVES)) {
       // 용마루 -- straight-skeleton
       console.log('용마루 지붕')
-    } else if (isGable) {
+    } else if (isGableRoof(types)) {
       // A형, B형 박공 지붕
       console.log('패턴 지붕')
-    } else if (isShed) {
+      isGableRoof(types)
+    } else if (isShedRoof(types, this.lines)) {
       console.log('한쪽흐름 지붕')
       drawShedRoof(this.id, this.canvas, textMode)
     } else {