global proc getNormals(string $tnode, vector $data[]) {
    int     $count = size($data);
  
    // Step 1: Decide what is selected.
    string $vertices[] = `filterExpand -sm 31`;
    // Individual vertices have NOT been selected so we 
    // go ahead as usual...
    if(size($vertices) == 0) {         
        string  $shapes[] = `listRelatives -shapes $tnode`;
      
        if(size($shapes) == 1) {
            int     $num_vertices[] = `polyEvaluate -v $tnode`; 
            string  $shape = $shapes[0];
            float   $norms[];
            vector  $ave;
                
            for($n = 0; $n < $num_vertices[0]; $n++) {
                $vertexStr = $shape + ".vtx[" + $n + "]";
                $norms = `polyNormalPerVertex -q -xyz $vertexStr`;
                $ave = getAverageNormal($norms);
                $data[$count] = << $ave.x, $ave.y, $ave.z >>;
                $count++;
                }
            }
        else  // tnode is a group node
            {
             string  $children[] = `listRelatives -children $tnode`;
             for($child in $children) {
                getNormals($child, $data);
                }
            }    
        }
    else
        {
        float   $norms[];
        vector  $ave;    
        for($vert in $vertices) {
            $norms = `polyNormalPerVertex -q -xyz $vert`;
            $ave = getAverageNormal($norms);
            $data[$count] = << $ave.x, $ave.y, $ave.z >>;
            $count++; 
            } 
        }
    }
  
// Used by getNormals()
global proc vector getAverageNormal(float $norms[]) {
    float   $x = 0, $y = 0, $z = 0;
    int     $numComps = size($norms);
    int     $numNorms = $numComps/3;
    //print("num norms = " + size($norms) + "\n");
    if($numNorms == 1)
        return <<$norms[0],$norms[1],$norms[2]>>;
    for($n = 0; $n <= $numComps - 3; $n += 3) {
        $x += $norms[$n];
        $y += $norms[$n + 1];
        $z += $norms[$n + 2];
        }
    return <<$x/$numNorms, $y/$numNorms, $z/$numNorms >>;
    }