The UPS plugin requires the dimensions for the shipping price calculations to check the maximum size of packages and to sedn it to ups to get correct rates with the products are not grouped.
You can try to change the lines:
$data.=$this->_createPackage($data, $variant, $rate, $order, true);
and:
$data.=$this->_createPackage($data, $product, $rate, $order, true );
to:
$data.=$this->_createPackage($data, $variant, $rate, $order, false);
and:
$data.=$this->_createPackage($data, $product, $rate, $order, false);
in the plugins/hikashopshipping/ups.php file so that it never sends the dimensions to ups. That might help you but it might also not work if ups requires them.
I don't know what world ship is ?