diff --git a/assets/jsons/flat.json5 b/assets/jsons/flat.json5
index ada15f1..51d4bd2 100644
--- a/assets/jsons/flat.json5
+++ b/assets/jsons/flat.json5
@@ -36,7 +36,7 @@
                 },
                 {
                     "field": "is_sink_",
-                    "type": "float",
+                    "type": "bool",
                     "title": "Is Sink",
                     "desc": "Whether this flat floor is used for sink floor.",
                     "default": "False"