I think this gets close to what your looking for

#! perl -slw
use strict;

my (@blocks, $datavertex);
# Build the structure
while(my $in = <DATA>) {
    if ( $in =~ /^88888/ ) {
        push @blocks, $datavertex;
        $datavertex = [];
        next;
    }
    my @vertex = ($in, scalar <DATA>, scalar <DATA>, 0);
    chomp @vertex;
    push @{$datavertex}, \@vertex;
}
push @blocks, $datavertex if @$datavertex; #! push the last block

# Accessing it
for my $block (0..$#blocks) {
    for my $dv ( 0 .. $#{$blocks[$block]} ) {
        for my $vertex ( 0 .. $#{$blocks[$block][$dv]} ) {
            print"[$block][$dv][$vertex] =>", $blocks[$block][$dv][$ve
+rtex];
        }
        print '';
    }
}
__DATA__
1
786.582394
1480.624270
2
877.141985
1284.635536
3
779.147607
1239.355735
4
688.588015
1435.344469
5
786.582394
1480.624270
88888
6
664.833374
241.139500
7
661.222659
245.226628
[download]

The output

22:44:50.88 C:\test>233619.pl
[0][0][0] =>1
[0][0][1] =>786.582394
[0][0][2] =>1480.624270
[0][0][3] =>0

[0][1][0] =>2
[0][1][1] =>877.141985
[0][1][2] =>1284.635536
[0][1][3] =>0

[0][2][0] =>3
[0][2][1] =>779.147607
[0][2][2] =>1239.355735
[0][2][3] =>0

[0][3][0] =>4
[0][3][1] =>688.588015
[0][3][2] =>1435.344469
[0][3][3] =>0

[0][4][0] =>5
[0][4][1] =>786.582394
[0][4][2] =>1480.624270
[0][4][3] =>0

[1][0][0] =>6
[1][0][1] =>664.833374
[1][0][2] =>241.139500
[1][0][3] =>0

[1][1][0] =>7
[1][1][1] =>661.222659
[1][1][2] =>245.226628
[1][1][3] =>0
[download]