choose shipment type based on volume and not according to the weight

[sephzero]

Hello, for my e-commerce website i need to choose shipment type based on volume of products and not according to their weight, is this possible to do?

Example:

i have to ship this 2 products

product 1 - 3kg - 1m^3
product 2 - 1kg - 0,5m^3

the amout of m^3 is 1,5, so i want the user can only choose shipment n.2

PS: i'm sorry for my bad english, i'm not so good at it..

Thankyou for your answers, cheers

[Radu]

it's not possible without modifying core files and database, there is no newbie solution from my point of view.

but some general lines:
1. add for ps_product a new field called volume, decimal(4,2)
2. modify classes/Product.php to fit the new field volume (check the weight field for instance where it appears and just duplicate the same thing for volume)
3. in admin/tabs/AdminProducts.php duplicate what you have for weight for volume (so you can add volume for each product)
4. in classes/Carrier.php modify the function getCarriers: loop through the cart items to sum the volume up and depending on the value take out some carriers from the $carriers array

a second solution for points 1-3 is using product features but here you are left with no validation of the volume field (mandatory, integer)