my $indata;
open( I, "<", "vrml.file" ) or die "vrml.file: $!";
{
    local $/;
    $indata = <>;
}

while ( $indata =~ /\[              # match open sq-bracket
                    ((?:\s*\d+){3}) # match 3 numerics
                    ,               # match comma
                    ((?:\s*\d+){3}) # match 3 more numerics
                    \]              # match close sq-bracket
                   /gx )
{
    my ( $x, $y ) = ( $1, $2 );
    s/^\s+// for ( $x, $y );
    my @x = split " ", $x;
    my @y = split " ", $y;

    # @x and @y each contain 3 numeric values

    my $axis = "x";
    for my $aref ( \@x, \@y ) {
        print scalar @$aref, " elements in $axis array: @$aref\n";
        $axis++;
    }
}