diff --git a/src/VirtualLeafpar.tmpl b/src/VirtualLeafpar.tmpl
--- a/src/VirtualLeafpar.tmpl
+++ b/src/VirtualLeafpar.tmpl
@@ -124,3 +124,5 @@ b3 = false / bool
 b4 = false / bool
 dir1 = . / directory
 dir2 = . / directory
+export_interval = 0 / int
+export_fn_prefix = CellData_ / string