If you are looking for a deep dive into the code and architecture, the provides a comprehensive breakdown of the engine's internal logic, while Fabien Sanglard's Game Engine Black Book: DOOM is widely considered the ultimate "paper" or book on how the technical magic of DOOM was achieved.

: Optimizing how floors and ceilings were rendered to save processing power.

The most famous "interesting paper" related to this topic is:

This paper and the related technical documents explain how DOOM achieved real-time 3D rendering on 1993 hardware by:

(often discussed in the context of Bruce Naylor's work or the early id Software technical blogs). Why it’s "Interesting"

: Avoiding slow floating-point calculations, which was critical for the CPUs of that era.

: Using BSP trees to split a 2D map into sub-sectors, allowing the engine to determine which walls to draw first without sorting every frame.