Questioned as to why it was so difficult to create the correct eyelines when lining up Catalogue-generated characters in dialogue scenes - from shot to shot and even within the same frame - Nanneman responded that of the 65, 536 character templates that his system had generated, it so happened that the majority of them turned out to be of a type that finds it difficult to maintain eye contact. Careful study of the sample scenes has indeed shown that in a large proportion of apparently mismatched eyelines, the characters portrayed are in fact very accurately looking at fluff on the other’s shoulder, the toes of their own boots, or a door handle in the background. Eyeline discrepancies between characters and objects were far rarer and can mainly be attributed to shortsighted or confused characters.
cf. The films of Harris Metcalf, who liberated the representation of eyes from the realm of physical realism, used eyeline angle as an expressionist device and whose characters’ unseeing eyes only ever met by accident.