my $subobj = $obj->subclass->new();

##</code><code>##

my $subobj = $obj->subclass();
# or, better, my $subobj = $obj->subclass_clone();

##</code><code>##

my $subobj = $obj->clone_into('Class::SubClass');
# ...
sub clone_into {
   my ($self, $subclass) = @_;
   return $subclass->new(%$self);
}

##</code><code>##

my $subobj = Class::SubClass->new(%$obj);

##</code><code>##

my $subobj = Class::SubClass->clone_from($obj);
# ...
sub clone_from {
   my ($package, $base) = @_;
   return $package->new(%$base);
}