[Paraview] Selecting Cell Data

[Kent Eschenberg]

How does one set the XML for a module that must use cell data? My module works as expected in these ways:

   - it will only connect to sources providing cell data
   - only variables attached to cells are shown in the array menu

But inside the new module's RequestData routine the call

   vtkDataArray *D = this->GetInputArrayToProcess( 0, inputVector )

returns a null. The superclass for the new module is vtkPolyDataAlgorithn and so when I dug in with the debugger I eventually, as expected, got to

   vtkAlgorithm::GetInputArrayToProcess( int idx, vtkDataObject* input)

where on line 305 the test

    if (fieldAssoc == vtkDataObject::FIELD_ASSOCIATION_POINTS)

evaluates to true. It therefore tries to find point data with the given name and fails. In other words, I need to change my XML so that fieldAssoc indicates that we want cell data.

Here's a part of the GUI xml:

======
      <Filter class="vtkCloud">
         <Input name="Input" class="vtkDataSet">
            <ArrayRequirement attribute="Cell" components="1"/>
         </Input>
      </Filter>
      <InputMenu id="inpMen" trace_name="Input" input_name="Input"
         property="Input"  label="Input"  help="Input to this filter" />
      <ArrayMenu id="arrMen"  input_menu="inpMen"  trace_name="Scalars"
         property="VariableForDensity"  label="Density Scalar"
         help="Input cell scalar used for point density" />
======

And here is a part of the server manager XMl:

======
         <InputProperty name="Input" command="SetInput">
            <ProxyGroupDomain name="groups">
               <Group name="sources"/>
               <Group name="filters"/>
            </ProxyGroupDomain>
            <DataTypeDomain name="input_type">
               <DataType value="vtkDataSet"/>
            </DataTypeDomain>
            <InputArrayDomain name="input_array1" attribute_type="cell"
               number_of_components="1" />
          </InputProperty>
         <StringVectorProperty name="VariableForDensity" 
            command="SetInputArrayToProcess" number_of_elements="5"
            element_types="0 0 0 0 2" > 
            <ArrayListDomain name="array_list" attribute_type="Scalars"
               input_domain_name="input_array1" >
               <RequiredProperties>
                  <Property name="Input" function="Input"/>
               </RequiredProperties>
            </ArrayListDomain>
         </StringVectorProperty>
======

My system:
   OS: Redhat 2.6.14-1.1656_FC4
   Compiler: gcc 4.0.2
   ParaView: 2.4.3

Thanks in advance!

Kent
Pittsburgh Supercomputing Center