Terraforming was the science of reshaping a planet to the specific needs of its new inhabitants.
When a Psi-moon detected the presence of a strong personality, it terraformed itself to mimic that person's mental landscape. This happened while Rimmer and Kryten were on such a moon, with the reshaping of the surface so violent that Starbug was destroyed. (RD: Terrorform)
One aspect of terraforming was the introduction of new oceanic lifeforms. The SSS Esperanto was on a seeding mission when one of their experiments got the better of them. The Despair Squid wiped out the crew and almost all the other seaborne life on the planet. (RD: Back to Reality)
Rimmer once found himself marooned on a planet with no complex lifeforms. Since the escape pod he had arrived in was looted from a seeding ship, he was able to use Eco-Accelerator rockets to terraform the planet in just 6 days. He named the planet Rimmerworld. The pod's genetic science enabled him to clone himself and populate Rimmerworld with copies that overthrew him and formed a corrupted society. (RD: Rimmerworld)
Kryten's nanobots took Red Dwarf apart and reshaped it into a dusty, wind-blown planet where they dumped all the parts of the ship that they did not need. After being captured, they turned the planet back into a spaceship. (RD: Nanarchy)
The Great GELF State tried to ride out a black hole by terraforming two planets, using gestalt beings as vast engines to reshape the surface for colonisation. The first used criminals as colonists, causing a massive breakdown in society. The second was ruled by The Rage, an entity comprised of furious innocent beings. Rimmer destroyed The Rage with the Oblivion Virus so his comrades could settle on the planet's surface. (Last Human)
Space Corps directive 723 states that terraformers are expressly prohibited from recreating either the English town of Swindon or the American city of Cleveland, depending on what source is used. (Red Dwarf 1996 Log Book, PBS Ident)