diff --git a/fcore/quad-tree.sml b/fcore/quad-tree.sml
index 7b18f63..2a949f4 100644
--- a/fcore/quad-tree.sml
+++ b/fcore/quad-tree.sml
@@ -1,6 +1,16 @@
 structure CollisionTree =
 struct
   local
+    fun findLastDot (str, pos) =
+      if pos < 0 then ~1
+      else if String.sub (str, pos) = #"." then pos
+      else findLastDot (str, pos - 1)
+
+    fun removeFileExtension str =
+      let val lastDot = findLastDot (str, String.size str - 1)
+      in if lastDot = ~1 then str else String.substring (str, 0, lastDot)
+      end
+
     fun finish acc =
       let val acc = List.rev acc
       in String.implode acc
@@ -16,10 +26,14 @@ struct
       | loop ([], acc) = finish acc
   in
     fun kebabCaseToPascalCase str =
-      (* capitalise first character in string *)
-      case String.explode str of
-        chr :: tl => let val chr = Char.toUpper chr in loop (tl, [chr]) end
-      | [] => ""
+      let
+        val str = removeFileExtension str
+      in
+        (* capitalise first character in string *)
+        case String.explode str of
+          chr :: tl => let val chr = Char.toUpper chr in loop (tl, [chr]) end
+        | [] => ""
+      end
   end
 
   structure BinTree =