How can I add a new measurement unit?

[panoss]

I need to add a new measurement unit for composite weight.
It 's gr/m^2, that is grammars per square meter, that's how carpets are measured.
I 'll have to create a variant field?

Then I 'll be able to add this new measurement unit?

How can I do this?

[GJC Web Design]

http://docs.virtuemart.net/manual/general-concepts/212-customfields.html

[panoss]

GJC thank you for answering but what do you mean?
That the measurement unit should be a custom field?

[GJC Web Design]

Yes, why not?

[panoss]

That 's what I'm gonna do, at least I 'll give it a shot.
But I want this field (well in fact two fields, the 'composite weight' and it's measurement unit 'gr/m^2') to appear only in the category of Carpets.
I don't want it to appear in the other categories (e.g in 'Furnitures' there 's no need for such a field) how can I do this?

Edit:
I created a custom field, it appears only if I set a value in the Product 's>Custom Fields> at the bottom of the page.
So I don't have to choose in which categories the field will appear, I only have to choose the products.
Do I understand it correctly?

[GJC Web Design]

correct