Existing buildings now represent the greatest opportunity to improve building energy efficiency. Building performance analysis
is becoming increasingly important because decision makers can have a better visualization of their building’s performance and
quickly make the solution for improving building energy efficiency and reducing environmental impacts. Nowadays, building
information models (BIMs) have been widely created during the design phase of new buildings, and it can be easily imported to
third party software to conduct various analyses. However, a BIM is not always available for all existing buildings. Even if a
BIM is available during the design and construction phases, it is very challenging to keep updating it while a building is aged. A
manual process to create or update a BIM is very time consuming and labor intensive. A laser scanning technology has been a
popular tool to create as-is BIM. However it still needs labor-intensive manual processes to create a BIM out of point clouds.
This paper introduces automatic as-is simplified BIM creation from point clouds for energy simulations. A framework of decision
support system that can assist decision makers on retrofits for existing buildings is introduced as well. A case study on a
residential house was tested in this study to validate the proposed framework, and the technical feasibility of the developed
system was positively demonstrated.