Forecasting accessibility issues of a mechanical assembly within 3D Digital Mock-up during the early stages of the engineering design will prevent the project from costly bottlenecks later. Documenting maintenance feasibility and manufacturing processes are no more internal requirements only but also customers requirements whatever their industrial field is. Studying Mounting and Dismounting activities serves both the Time to Market and Service Quality criteria of any industrial good. DMU Path Planner provide tools for better addressing these activities thanks to automatic collision free motion and path planning. The product workbench provides highly-efficient path planning commands for collision-free path planning to facilitate design, serviceability and manufacturability studies resulting in time savings due to faster computation times and improved quality of the planned path.