Limits of Transferring User-Defined Quantity Takeoff Rules in 2D CAD and 3D BIM Using Semantic Vertices

In construction projects, dimensioning automation is now implemented with relatively high precision in both 2D CAD and 3D BIM environments when conditions are clearly defined. For identical or similar objects with the same attributes, dimension-based quantity takeoff formulas can be automated, and such automated formulas can be repeatedly applied as long as the geometric form and attributes remain unchanged. However, this automation is feasible only within limited environments and under pre-defined rules. Once the geometry is slightly altered or geometric identity is disrupted, directly applying the existing automated mechanism becomes structurally constrained. This is because (1) quantity takeoff formulas are difficult to standardize universally, (2) object orientation is often difficult to determine consistently, and (3) even minor geometric changes can alter the meaning of dimensions, making automatic interpretation problematic. Accordingly, this study aims to systematically and experimentally analyze the practical limits of transferring semantic-vertex-based quantity takeoff formulas. To this end, a single isolated footing is adopted as a common reference object, and the limits of user-defined dimension-based automation in 2D CAD and 3D BIM environments are evaluated through three core comparisons: 1. 2D–3D reliability comparison: consistency of final quantity results within an acceptable tolerance range for the isolated footing; 2. User dependency assessment (3D-focused): the extent to which quantity takeoff formulas in 3D BIM depend on user judgment; 3. User-defined dimension transfer limits: the practical limits of transferring user-defined dimensions between geometrically identical isolated footings in both 2D and 3D environments. Through this analysis, this study empirically confirms that geometric variation is a key factor structurally constraining the transferability of user-defined quantity takeoff formulas. Furthermore, as future work, it proposes directions for linking automated dimension generation with quantity takeoff formulations.