diff --git a/src/kiri-mode/cam/ops.js b/src/kiri-mode/cam/ops.js
index 2a0b190a..7500f522 100644
--- a/src/kiri-mode/cam/ops.js
+++ b/src/kiri-mode/cam/ops.js
@@ -1543,6 +1543,10 @@ class OpShadow extends CamOp {
             progress(index / total);
         }, genso: true });
 
+        if (terrain.length === 0) {
+            throw `invalid widget shadow`;
+        }
+
         state.shadowTop = terrain[terrain.length - 1];
         state.center = tshadow[0].bounds.center();
         state.tshadow = tshadow; // true shadow (bottom of part)
diff --git a/src/load/file.js b/src/load/file.js
index 9a4f28e3..2ca0f946 100644
--- a/src/load/file.js
+++ b/src/load/file.js
@@ -43,7 +43,6 @@ const types = {
 
     png(data, file, resolve, reject) {
         load.PNG.parse(data, {
-            ...opt,
             done(data) {
                 resolve({ mesh: data, file });
             }