diff --git a/src/util/qpolygon-utils.js b/src/util/qpolygon-utils.js
index 33737856..6e25c18d 100644
--- a/src/util/qpolygon-utils.js
+++ b/src/util/qpolygon-utils.js
@@ -7665,7 +7665,11 @@ export const drawRidgeRoof = (roofId, canvas, textMode) => {
           .filter((line) => (line.x2 === ridge.x1 && line.y2 === ridge.y1) || (line.x2 === ridge.x2 && line.y2 === ridge.y2))
           .filter((line) => baseLines.filter((baseLine) => baseLine.x1 === line.x1 && baseLine.y1 === line.y1).length > 0)
         basePoints.sort((a, b) => a.line.attributes.planeSize - b.line.attributes.planeSize)
-        hipSize = Big(basePoints[0].line.attributes.planeSize)
+        if (basePoints.length > 0 && basePoints[0].line) {
+          hipSize = Big(basePoints[0].line.attributes.planeSize)
+        } else {
+          hipSize = Big(0) // 또는 기본값 설정
+        }
       }
       hipSize = hipSize.pow(2).div(2).sqrt().round().div(10).toNumber()