Abstract: Various versions of BIM models will appear in different stages of the entire life cycle of a
building, and the differences among these models can provide support for the decision-making in the
construction and operation of the building. Most BIM model comparisons are based on visual
inspection, manual counting, and selective inspection of attributes. Although some scholars and
relevant institutions have studied some methods of automatic comparison of BIM models, most of
them rely on the ID of components in the model, and the results of comparison cannot be directly
reflected in specific components and attributes. Aimed at these problems, a comparison method of BIM models was proposed based on shape distribution and registration position, extracting features
from components for component matching and compareing BIM models on the component level.
Firstly, shape distribution of the components was constructed based on their geometric information to
calculate the similarity between the shape distribution of components of similar types. Secondly, the
positions of the components were matched and the similarity between the positions was calculated.
Then two similarity degrees were combined to match components and the differences between
matched components were compared. Finally, the difference between models was obtained, and
WebGL was used for visual presentation. This method disregards the influence of the changes of
component ID on model comparison, capable of working out the differences among models on the
component level.

Key words: building information modeling, model comparison, ignore component ID, shape distribution, components matching, visual presentation