diff --git a/src/main.lua b/src/main.lua
index 70cebee..518df06 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -656,8 +656,8 @@ end
 local function VP_splitstack(_stack, x)
     local stack = _stack["stacks"]
     local dimensions = _stack["dimensions"]
-    local sx = dimensions["sx"]
-    local sz = dimensions["sz"]
+    local sx = dimensions["x"]
+    local sz = dimensions["z"]
     local height = _stack["height"]
     local stacks = {}
     local unevenstack = {}