Dimensions to calc shipping in Product

[m4ss4cr4t10n]

Hi,

I'm from Brazil, and I've been trouble to made a module that calc shipping of the product, because I need to implement a way to register the dimensions of the product in centimeter near weight, like:

Weight (kg):
Wide (cm):
Height (cm):
Depth (cm):

So I want to make a module. But I need help, to know how can I add those fields in the registration of the product.

Is there any way to do that with a module?

Regards,
Danilo