[vtkusers] vtkBooleanOperationPolyDataFilter with SetOperationToDifference operating on identical vtkPolyData

[Toby Rule]

Is there a way to set up a vtkBooleanOperationPolyDataFilter so that, when it is used to take a boolean difference between identical vtkPolyData, it will result in an empty vtkPolyData? For instance, if I start with

    vtkPolyData * output 

and do ...

    vtkSmartPointer<vtkBooleanOperationPolyDataFilter> diffFilter = 
      vtkSmartPointer<vtkBooleanOperationPolyDataFilter>::New();
    diffFilter->SetOperationToDifference();
    diffFilter->SetInputData(0,output1);
    diffFilter->SetInputData(1,output1); // set input and output to same geometry

... the result of the diffFilter operation appears to be identical to output1. For my application, the result should be an empty set.

According to this VTK Journal article http://www.vtkjournal.org/browse/publication/797 the algorithm assumes there are no coplanar triangles, so it may be that what I ask is impossible, and I need to look at a solid modeling library.

Thanks,

Toby

The information contained in this transmission is intended only for the person or entity
to which it is addressed and may contain II-VI Proprietary and/or II-VI Business Sensitive
material. If you are not the intended recipient, please contact the sender immediately
and destroy the material in its entirety, whether electronic or hard copy. You are
notified that any review, retransmission, copying, disclosure, dissemination or other
use of, or taking of any action in reliance upon this information by persons or entities 
other than the intended recipient is prohibited.