Abstract: A comprehensive survey on the automatic recognition and understanding methods
for engineering drawings is proposed. Target of interpretation of engineering drawings lies on
automatic extraction of explicit descriptions (e.g., graphical primitives, engineering symbols,
engineering entities) and implicit semantics behind the drawings. Vectorization, recognition of
engineering symbols and engineering entities are analyzed systematically. Based on these,
performance evaluations and benchmarks are also proposed. Finally existing difficulties and
future research are discussed.

Key words: engineering drawings, understanding, recognition, knowledge representation;
vectorization