[vtkusers] GetMTime & rendering\pipeline updating

[Dmitry]

Hi All!

Is there way to implement such behaviour -
the underlying vtkPoints object (exactly, the vtkDataArray - memory for points data) for polydata not to 
be accessed during pipeline updating\rendering until the modification time for this vtkPoints (via Modified 
method) not be invoked? 
The doc says "Update the modification time for this object. Many filters rely on the modification time to 
determine if they need to recompute their data." for vtkObject::Modified. In this citation I confused with 
"_Many_ filters". Can _any_ library filter not follow this? Is this behaviour mandatory? Second, as I refer 
src. code data, if the immediate mode is off, data not to be accessed during rendering. Am I right?

Initial problem - I need to modify vtkPoints by worker thread (via SetPoint) while actor being rendered in 
context of main thread. Sync. only Modified & GetMTime greatly simplify app.

Thanks in advance.