3D action-adventure like Tomb Raider was unprecedented at the time, and the development team took several months to find a way to make Gard's vision for the game work on the hardware of the time, in particular getting the player character to interact with freeform environments. Tomb Raider used a custom-built game engine, as did many games of the era. The engine was designed and built by Douglas with assistance from Rummery. Rummery created the level editor, which allowed for "seamless" creation of levels. According to Rummery, the decision to build the game levels on a grid was the key breakthrough in making the game possible. It is Core Design's contention that, prior to the development of Tomb Raider, they were "struggling somewhat" with 32-bit development. The level editor program was designed so that developers could make rapid adjustments to specific areas with ease. Another noted aspect was the multi-layered levels, as compared to equivalent 3D action-adventure games of the time which were mostly limited to a flat-floor system with little verticality. The interlinking room design was inspired by Egyptian multi-roomed tombs, particularly the tomb of Tutankhamun. The grid-based pattern was a necessity due to the d-pad-based tank controls and the Saturn's quad polygon-based rendering technology. Levels were first designed using a wireframe construction, with each area at this stage having only links to other areas of a level and walls. The team then added architecture and gameplay elements like traps and enemies, then implemented the different lighting values. Due to time and technical limitations, planned outdoor areas had to be cut. The choice of a third-person perspective was influenced by the team's opinion that the game type was under-represented when compared to first-person shooters such as Doom. The third-person view meant multiple elements were difficult to implement, including the character and camera control. The camera had four pre-set angles, which seamlessly switched depending on the character's position and the level progress. For standard navigation and combat, the camera was fixed on a particular point and oriented around Lara while focusing on that object. Lara's twin pistol set-up was in place from the early prototypes. The aiming system was designed so that each gun arm had an aiming axis, with a shared "sweetspot" where both guns fired at the same target. For underwater environments, the effects were created using gouraud shading to create real-time ripple and lighting effects. Audio The