Performing complex solar shading analysis to take into account the sun's path and solar penetration on large buildings has historically consumed very many CPU cycles for IES "Virtual Environment" (3D building physics) simulation users. One particularly complex model took almost 2 weeks to process. A description of the collaboration between IES and EPCC to apply HPC practices to the solar analysis algorithm and benchmark results will be presented. Additionally we will cover the pitfalls found when integrating the MPI solution in a commercial environment and how we addressed these. The presentation will conclude with a brief description of in-progress and potential future developments with EPCC.