How to add a product property to the cart?

Question

1C-Bitrix

The problem is the following: there is a website for an online store selling roofing materials. Products are divided into two categories:

1. goods sold by the piece. their price depends on the quantity of the selected product
   
2. goods, the price of which depends on the area of ​​the goods. for such products, the user must specify the sheet width, sheet length and number of sheets. after that, the total area is calculated by the formula:
   общая площадь = ширина*длина*количество листов
   and now the price is calculated as
   цена = площадь*стоимость одного квадратного метра
   

So it turns out that for the second category, you need to add the properties of length, width and number of litas to the product. I did it. But now I can't add these properties to the cart when adding a product. The Bitrix documentation says that you can only add properties of the list type or multiple properties. But the properties of length, width and number of sheets are not. How to be in such a situation?

Answer 1

https://dev.1c-bitrix.ru/api_help/sale/classes/csa...
any property can be added\get\changed