Ecwid allows to configure shipping in many different ways, including carrier-calculated methods, user-defined options and fixed product rates. User-defined and carrier-calculated shipping rates may depend on an order weight, number of items and a customer destination. Please refer to this article in our knowledge base for the detailed information:
Talking of shipping package volume, Ecwid currently doesn't support such settings yet. But the suggestion to add the 'Package dimensions' option to the product is very popular among our customer, so if you find this functionality useful, please, vote for this idea here
. We will notify you when it is added to Ecwid.
In the meantime, I believe there is a way to set up shipping in your store that will meet your requirements without setting up product dimensions. For example, you can manually set up an additional fixed rate that will cover your expenses for each product depending on its real sizes. Please detail your needs so we can recommend you a solution.