The overall objective of the planning and design process for a factory layout is to generate and assess layout design proposals and choose the alternative that enables the factory to operate according to set performance targets while providing a safe work environment. The factory layout is frequently planned and designed in a virtual environment. This facilitates creation, simulation, visualization, and assessing potential future outcomes of the factory setup, without the need of intervening with physical objects. However, the planning and design of factory layouts is typically based on the experience of the expert and software tool user undertaking the planning and design activity. The activity depends on information generated by several cross-disciplinary functions and experts in, for example, product development, process planning, resource descriptions, ergonomics, and safety. The information provided by these functions and experts is also frequently generated with several software applications and depends on the experience of the software tool user performing their specific activity. This experience-based, manual, and serial approach to plan and design factory layouts, considering a wide range of parameters, is a cumbersome, non-integrated, and subjective process with a high risk of human error and faulty inputs and updates. The aim of this research is to develop methods, demonstrators, and a framework to support multiobjective planning and design of factory layouts. The purpose is to bridge gaps between the cross-disciplinary functions and experts involved in the planning and design of factory layouts. The research presents and tests ways to assist the software tool user when performing factory layout tasks. One approach is by adding rules and regulations to resources and equipment in the virtual environment. Further, the research demonstrates how simulation-based multi-objective optimization can assist the planning and design of factory layouts, supporting the generation and assessment of a multitude of layout design proposals, based on defined objectives and constraints of factory layouts. The methods, demonstrators, and framework developed in the research enhance quality and objectivity and provide risk mitigation in the process of planning and designing factory layouts.