Abstract: A technology for checking the completeness of dimensioning and analyzing the
dimensional chain was proposed to solve problems, such as complicated structure of the 3D model
based definition (MBD) model, error-prone dimensioning and the difficulty of manual check. The
spatial dimensions were converted into a series of matrices to ensure the completeness of the
dimensions at 3D level, based on which the sizes of each member of the dimensional chain were
calculated to verify the rationality of the design. Matrix was used to express and store the dimensions
on the 3D model and the redundancy and deletion of the dimensions was judged by the position and
quantity of dimension nodes. Then the to-be-judged dimensional chain was extracted from the model
for analysis and verification to ensure the accuracy of product manufacturing information
transmission and an inspection report was produced. The feasibility of the method was verified by
using the connecting rod of a certain type of marine diesel engine, which greatly reduced the
inspection time and the design error rate and improved the design efficiency of the staff.

Key words: model-based 3D definition, product manufacturing information, dimensioning, completeness
check, dimensional chain analysis