Update README.md

README.md

@@ -283,7 +283,7 @@ update() : void
 
 Updates the tiles to render and kicks off loads for the appropriate tiles in the 3d tile set.
 
-Both `group.matrixWorld` and all cameras world matrices are expected to be to date before this is called.
+Both `group.matrixWorld` and all cameras world matrices are expected to be up to date before this is called.
 
 ### .getBounds