Postie features a number of different mechanisms to pack boxes for accurate shipping quotes.
When chosen, each individual item in the cart will be packed in a box fitted to the item. When purchasing multiple quantities of the same item, each item will still be in an individual box.
This will fit all items in one or many boxes, as defined by you, or pre-set boxes defined by the provider. Any items that do not fit these box constraints are fitted to an individual box.
Given a collection of products, Postie will try to fit all items into a single box. Care should be taken with this approach, if an order contains large or bulk items, they might exceed provider allowances.
Our box packing algorithm is volume based, and whilst it provides good results in most cases, it will never be as accurate as a real person packing a box (see BIN Packing Problem).
At a high level, the algorithm works like this:
Refer to the docs for further reading.
Available for Craft 3. Get it from the plugin store.