mMIP = vtkVolumeRayCastMIPFunction::New();
mMIP->SetMaximizeMethodToScalarValue();
mMapper = vtkVolumeRayCastMapper::New();
mMapper->SetVolumeRayCastFunction(mMIP);
mMIP = vtkVolumeRayCastMIPFunction::New();
mMIP->SetMaximizeMethodToScalarValue();
mMapper = vtkVolumeRayCastMapper::New();
mMapper->SetVolumeRayCastFunction(mMIP);