Complex price calculation of a product

[vigier]

Hi,

I've been trying some various options, but I can't get it done without creating a lot of different variants for one product.
Let's say I sell bricks at custom size. The user can input the length and the price is a base price + length x price_per_length with a minimum price for the total. That's an easy one (had to edit the price_per_letter part of the customtextplugin).
You can also get various colors. If you want black ones or white ones, that's the standard price. But if you select red or blue, the base price and the price_per_length are higher.
And there are 5 different heights to select. If you want the 2 smallest, that's the standard price. But if you select the 3 larger ones, the base price and the price_per_length are higher.
And there are a few extra options that have a price that doesn't depend on the size.

I have a table to determine the right base price and price_per_letter. But how can I create such a product? Or do I have to make some sort of plugin/form to do this? And if so, how should I do that?

I hope that anyone here can help me.