Ajeh:
If you had a shipping cart of 150lbs, it would divide the weight by 50 and get 3 boxes for 50lbs each. Then it would request a quote for 50lbs and multiple the returned shipping cost by the number of boxes and give your the rate ...
This is not an exact science, as it assumes you are using 3 50lb boxes for this order in the quote ...
It is fairly accurate, but you would need a much more customized approach if this is not "correct enough" for your shipping needs ...
Personally I think this is far from 'fairly accurate' and can lead to all sorts of problems.
I realise that I'm not going to be telling you (Ajeh) anything that you don't already know, but for those that don't think this through, take the following examples:
Lets assume that the maximum shipping weight is 50kg.
Lets us also assume that one of the products in the store weighs 60kg. When this item is placed in the cart the quote will be based on 2 parcels weighing 30kg each. This is all very well if the product can be cut in half for delivery, but if it can't the customer will be quoted for a delivery method that simply isn't possible.
Another more likely scenario.
Product weighs 20kg.
Customer orders one of these. The quote is fine.. 1 parcel @20kg.
Customer orders two of these. The quote is fine.. 1 parcel @40kg
Customer orders three of these. The quote will be invalid. 2 parcels @30kg ea. Can we really place 1.5 products per parcel? I think not.
The end result being that the entire order will be significantly under quoted, because in reality 3 parcels are needed rather than the 2 being quoted.
I could go on with more examples, but I think this should suffice.
FWIW (also for everyone other than Ajeh), on the surface, splitting overweight parcels into smaller ones may seem like a simple thing to achieve, but in practice it is quite the nightmare. I've actually spent 100's (1000s?) of hours working on a solution to the problem, and in the end I simply gave up on the idea, as such, the 'ozpost' module will only quote for a single parcel regardless of total weight, and if that total weight exceeds what any given carrier will handle it doesn't provide a quote for that carrier. If it is too heavy for all available carriers it generates a message that shipping quotes will be provided in due course (Actually this is only one of the options ozpost provides under these circumstances). The ozpost 'philosophy' is that if can't provide an accurate quote it is best to not quote at all.
I will stress that I'm not trying to be critical over the way 'native' Zencart handles this. In fact, based on my own efforts this 'simplistic' method, although prone to the shortcomings mentioned, is actually more reliable than most of the more complex methods that I've experimented with, and for those that are aware of the possible problems, the ozpost module also allows its quotes to be based on the 'zencart method' rather than the ozpost 'single parcel' method.
This is not intended to be a promotion of the ozpost module (which is only useful to Australian merchants anyway). It is mentioned mainly to demonstrate that I have more than a little experience on this topic and that I'm fully aware of the problems and difficulties involved.
It may seem like it should be quite easy to achieve the desired results.. people have no difficulty at all in packing items into multiple parcels, but creating code to replicate what people do with barely a second thought is a whole new ballgame that gets very complex, very quickly.
Cheers
RodG
NOTE: We are sorry that Rod is no longer with us.
We are grateful for all his contributions to the Zen Cart community.
Ozpost - The Ultimate Shipping module for Australian Merchants. Click these links for its Homepage, or Download from Zen-Cart.com.
