antonyms - what is the opposite of the word 'flat'?

• The surface of the colony* is flat and rugged.


• The surface of the colony* is not flat and rugged.

*(a colony of fungi)

Flat is in this case refers to the elevation of the colony. From the side view, it's flat, like a computer disc.

What is the opposite of flat, for this context? Is it non-flat?