diff --git a/interp/grid/gmsh.py b/interp/grid/gmsh.py
index d4cb2aa..33f1fcc 100644
--- a/interp/grid/gmsh.py
+++ b/interp/grid/gmsh.py
@@ -45,6 +45,7 @@ class gmsh_grid(grid):
 
 
     grid.__init__(self)
+    self.tree = KDTree(self.verts)
     gmsh_file.readline() # $EndNodes
     gmsh_file.readline() # $Elements