[vtkusers] TCL/TK check existance of VTK-object

[Mathijs Dijk]

Hello vtkusers!

Anybody know the TCL/TK syntax for checking if a vtk-object already exists?

I tried 
      
if {[info exist lutBG] == 0} {
   vtkLookupTable lutBG
}

[info exist lutBG]  returns 0 somehow... :(

greetz
Mathijs Dijk