Laravel collection sum with pivot table's field

Here my db tables:

**orders:**
id, customer_id, date .....etc

**packagings**
id, code, name .....

**products**
id, code, name, weight .......

And 2 manytomany tables with pivot :

**packaging_product:**
packaging_id, product_id, quantity

**packaging_order:**
packaging_id, order_id, quantity

To get total weight of one order i have this attribute in my order model:

public function getWeightAttribute()
{
    $tot_weight = 0;
    foreach ($this->packagings as $pack) {
        $tot_weight += $pack->weight * $pack->original['pivot_quantity'];
    }
    return $tot_weight; 
}

Is there an more elegant method using eloquance collections ?

via Polarix