Help with product options please

hi i am new to zen cart would like to no if this is possible and how to implement it ., i want to set up website for foam conversion, i want customers to be able input length depth width of a piece of foam and the zen cart to calculate the total cost formula would be length x width x depth / 144 x 0.4
any suggestions i would be more than grateful
thanks tony

Example using Rope as product...tutorials/faq link top of this page should also help
http://www.dezinashop.com/demo/index.php?main_page=product_info&products_id=154

thanks for your help , but nothing in faq or your site that resolves the problem..

i want customers to be able input length depth width of a piece of foam and the zen cart to calculate the total cost formula would be length x width x depth / 144 x 0.4
This requires "Dependant" attributes to do correctly and ZenCart does not have support for dependant attributes

A work around you might find acceptable would be to divide up your product offerings into your stock max dimensions or standard dimentions where you maximize use.

Could be widths of upto with a max length
24inch
36inch
48inch
etc

Then add attricutes for depths

Results in more individual products but workable

thanks for your help , did not want to introduce any script that might upset the the zen core . i thought i might have to do it that way
thanks again black belt