diff --git a/cameo/fped2d2z.pl b/cameo/fped2d2z.pl
index e4c5fe9..01df3fd 100755
--- a/cameo/fped2d2z.pl
+++ b/cameo/fped2d2z.pl
@@ -14,8 +14,10 @@
 
 sub usage
 {
-	print STDERR "usage: $0 [-r] [Zin=Zout ...] prefix [file ...]\n\n";
+	print STDERR "usage: $0 [-r|-t Zmax] [Zin=Zout ...] prefix ".
+	    "[file ...]\n\n";
 	print STDERR "  Zin=Zout  replace Zin with Zout\n";
+	print STDERR "  -t Zmax   set the top of the piece\n";
 	print STDERR "  -r        reverse Z stacking. Also swaps X and Y.\n";
 	exit(1);
 }
@@ -25,6 +27,10 @@ if ($ARGV[0] eq "-r") {
 	shift @ARGV;
 	$reverse = 1;
 }
+if ($ARGV[0] eq "-t") {
+	shift @ARGV;
+	$top = shift @ARGV;
+}
 &usage if $ARGV[0] =~ /^-[^0-9]/;
 
 while ($ARGV[0] =~ /=/) {
@@ -55,6 +61,12 @@ if ($reverse) {
 	}
 	%z = %t;
 	print "0 0 $zmax\n\n";
+} elsif (defined $top) {
+	for (keys %z) {
+		($t{$top-$_} = $z{$_}) =~
+		    s/^(-?\d+(\.\d*)?)\s+(-?\d+(\.\d*)?)/$1 $3/mg;
+	}
+	%z = %t;
 } else {
 	print "0 0 0\n\n";
 }