Automatic comparison of time-variant BIM models facilitates value-added applications during the building life cycle. This paper addresses a solution capable of exploring changes between point clouds and BIMs (Scan-vs-BIM) or between time-variant BIMs (BIM-vs-BIM). To this end, a change component identification (CCI) algorithm is proposed to determine changing states, spatial locations, and semantic information of the change components. In that, CCI realizes an object-oriented strategy and enables exploration of the local geometry of object shape and comparison of object similarity without being limited to specific targets. Validations demonstrate the effectiveness of CCI, which achieves an accuracy of up to 93% and 80% in the BIM-vs-BIM and Scan-vs-BIM cases, respectively. The proposed method is expected to improve the automation level to document construction progress or confirm discrepancies between as-is and as-built BIMs.