Factory layout planning is essential for manufacturing companies when designing or redesigning production systems. Layout planning usually involves 2D CAD applications, sometimes based on faulty data. Difficulties in communicating and discussing layout alternatives using such applications can lead to critical errors, yielding inaccurate simulation models producing poor results. This paper aims to investigate and evaluate the usefulness of realistic 3D layout models in the layout planning process, addressed by an industrial study of how existing methods for visualization can be applied. This paper shows that utilizing a realistic and accurate layout model allows for fruitful discussions while several potential mistakes can be avoided. It also shows benefits in evaluating a layout and the model's accuracy in immersive virtual reality where a better perspective of the layout can be acquired. Having such evaluated layout models will enable more accurate simulation models for planned changes, based on real physical requirements.