The invention is applicable to the technical field of
computer aided design, and provides an automatic tolerance labeling method based on a multi-
modal large model, which comprises the following operation steps: receiving an STP file of an
assembly as input, analyzing the structure of the
assembly, calculating geometric information of parts and feature surfaces, distributing a
unique identifier and establishing an
assembly tree; and through shell part identification and a
centroid-based iterative RANSAC profile
extraction algorithm, generating a multi-view overall image and a profile image. According to the automatic tolerance labeling method based on the multi-
modal large model, the manual labeling time is greatly shortened by automatically extracting geometric information and generating part description and tolerance labeling, and through guidance of a rule base and an
international standard, it is guaranteed that tolerance labeling is standard and unified, the risk of human errors is reduced, and the accuracy of the manual labeling is improved. The multi-
modal large model is combined with geometric data and
natural language description, comprehensive understanding of part functions and assembly relations is achieved, the reasonability of tolerance marking is improved, and the method is suitable for multiple parts.