Gobotron resembles an apple core, with a small metallic sphere fixed in its center. This is explained by Leader-1 to be old Gobotron, that is in decline and inhabited by illegal aliens and modified rejects. While a new spherical surface with numerous levels is currently being constructed, with only its separated north and south hemispheres completed, where the current generation of Gobots reside.
The idea however of a new surface constructed over a planet's recent one would be utilized in the Transformers Beast Machines. Where it is explained a new surface was built over old Cybertron. Where the Autobot descendants; the Maximals, reside in a scaled down city landscape..