Shipping weight and dimensions

How do we handle shipping when we ship a box of a product or a case of the product.  Attributes does not allow us to add dimensions different that the case for the box, so shipping is not adjusted by dimensions for the box if we load the case as the initial product.  Is there a way, without adding a different product for the box, to make adjustments to dimensions?

Which Shipping Provider plugin are you using?

USPS. However, I don’t see how that matters, doesn’t every shipping widget, ( UPS, FedEx, DHL, USPS), all use a combination of weight and product dimensions to calculate costs? The difference, is it’s the same product code in a case as the boxes inside. Weight and dimensions are different. Do I really have to set it up as two different codes?

Some shipping providers have Packing Type settings, and some don't.  USPS does not.  UPS has
>Pack By Dimensions
>Pack By One Item Per Package
>Pack By Volume

I believe that the USPS plugin is not very 'smart' about packing, and will use the 'Pack By Dimensions' algorithm (although it may depend on version of nopCommerce).  That packing will get total volume and total weight (across all items in cart), and if exceeds certain maximums, will just divide up the weight into a number of equal size 'packages'.

So, did you test the cart/rates?  I.e. if you do create the separate 'case product', compare the USPS rates and see how they differ.   If your 'case' has additional weight from a box and packing materials, then you may see a difference.

The problems comes when you use a shipping method to ship a product(s), say a bottle of wine, with weight 1.2kg size 300mm x 100mm x 100mm
A customer buys 18 of them and the shipping calculation is done using the cube root method to calculate the volumetric dimensions and weight and you get a cost to ship the total package.

That’s fine. The problem then comes when you pack it and need to make labels for the shipment. All you have is the single product dimensions and weight.
As it ends up you put the 12 bottles in one box and 6 bottles in another box and then you need two labels. What weight and dimensions do you send the Shipping methods to make the labels ?

I guess you need to manually enter the number of boxes and physical dimensions, then send that to shipping provider to make a consignment(s) and then print the labels.
Granted there is no existing spot in the shipment for the actual physical details to be stored.

Unless I am missing something it is custom development but has anyone done anything for this common scenario they want to share ?

Currently, Shipping Provider plugins really only provide "estimates" of the shipping methods/amount so that the customer chooses one and the shipping amount is part of the order subtotal.  Some third party shipping provider plugins will do additional 'integration' with the carrier to send order information / items so that the actual shipment creations can be done online at the carrier's site (or 3rd party like a Ship Station).

However, the bottom line is that physically packing the boxes is done by a person, and thus the final "packages" (weight and dimensions) is not really known until then.   How you pack your boxes is going to be dependent on your items (e.g. fragile items may need lots of packing material that takes up space; heavy items may need to be packed separately [nopC does support product "ship separately"]), and the sizes of the boxes that you have.

Most carriers charge by weight, so the estimate $ amount charged for shipping should be close, but dimensional weight could impact that.  The cubic root method does a fair job of doing the estimate, unless you have many lightweight items that would cause dimensional weight to apply.  Also, cubic root does not know what size boxes you have.

Shipping Director (shameless plug ;) has an additional Packing rule that uses a "single box size, first fit" algorithm.  We've recently added (still undocumented) a "Stacking" algorithm (for stacking items like traffic safety cones), and we're working on an "optimal bin packing" algorithm (computationally expensive and difficult to implement).  That said though, nopCommerce does not support any built-in 'integration' so that the packing information could be put on the order (or better yet, automatically create Shipments).  The Order itself is not in existence until the customer confirms, so it's not possible to use Order Notes or create the Shipments, unless a third party plugin can 'cache' the information somewhere and defer putting it on the order until the order exists.