Early animation tools in the 1990s were so primitive that Doom's lead artist, Adrian Carmack, relied heavily on the 'undo' key in Deluxe Paint to create the game's iconic sprite animations. Carmack revealed this unconventional method in a recent interview on YouTube.
Instead of sophisticated animation software, Carmack developed his own workflow. He utilized the undo and redo functions within Deluxe Paint to cycle through frames, effectively building animation loops. This approach was necessary because Doom's animations, unlike modern game animations, consisted of distinct, frame-by-frame movements rather than smooth, interpolated transitions. This method allowed for the creation of character and weapon animations using a limited number of frames, a necessity driven by programmer John Carmack's constraints on animation resources.
Carmack noted that this process was not without risk. The constant use of undo functions meant that there was always a possibility of accidentally deleting work. However, he developed a cautious approach over time, making significant data loss a rare occurrence. Despite the rudimentary nature of the tools, Carmack and his colleagues at id Software were reportedly impressed by the innovative solution that brought Doom's distinct visual style to life.