Change product weight/tax in checkout

[supersplet]

I use custom field where user select one of two versions. Now we have some changes in system and we need second option to use different tax and different weight - we can't use child product (which would solve his), so we need to check in checkout if product has custom field with ID XX and if it does, change his weight and tax. How could I do that and is it even possible to do it without causing any problems at other things?

[admin]

hello, i would suggest you to use a custom calculation plugin that manages the weight as you'd need and calculates desired tax as needed.

our opc uses VM's function to collect weight's of the products, there are some techniques that allow you to update any products data as needed from within a system or Vm plugin, but i'd need to know what exactly you'd expect me to do in this matter.

in next OPC version that i'll release this week, there is a new system plugin called "pricemod" which allows to set quantity prices of a variant per quantity of whole group of a parent product. the way it modifies product's object to force the quantity price can be used also to modify the weight of the product if needed.

the price mod plugin does:

parent that has 300 variants (such as adler tshirt with 30 colors and 10 sizes) and each thirt/size has another price but prices from 1... 11 quantity receive standard price and 12+ receive discounted price, the plugin allows to select discounted price if there is 6 products on one color+size and another 6 products of color+size (normally VM wold require to have 12+ per each)

best regards, stan