diff --git a/src/experimental/tf_x_twist.scad b/src/experimental/tf_x_twist.scad
index faae1da4..2d2f6648 100644
--- a/src/experimental/tf_x_twist.scad
+++ b/src/experimental/tf_x_twist.scad
@@ -11,6 +11,6 @@ function tf_x_twist(size, point, angle) =
         ylen = size[1],
         y_offset = ylen / 2,
         a_step = angle / xlen,
-        y_centered = [point[0], point[1], 0] + [0, -y_offset, 0]
+        y_centered = [point[0], point[1], is_undef(point[2]) ? 0 : point[2]] + [0, -y_offset, 0]
     )
     rotate_p(y_centered, [point[0] * a_step, 0, 0]) + [0, y_offset, 0];
\ No newline at end of file