Some system models may contain numerous detailed components and a large physical size. It will be prohibitively expensive to resolve and solve all the features. A sub-modeling (or "Zoom-In Model" in Icepak jargon) approach provides best of both worlds.
First the system level model is setup and solved for. Next a rectangular sub-region is defined as a Zoom-In Model in Icepak. This new model is created from the system model with all the objects inside the sub-region. The user then will add features and new objects to be solved for in the Zoom-In model. The boundary conditions for the Zoom-In model are automatically handled by Icepak. The 30-minute video below shows the detailed workflow with step-by-step instructions.