Path planning and re-planning for serial 6 degree of freedom (DOF) robotic systems is challenging due to complex kinematic structure and application conditions which affects the robot's tool frame position, orientation and singularity avoidance. These three characteristics represent the key elements for production planning and layout design of the automated manufacturing systems.The robot trajectory represents series of connected points in 3D space. Each point is defined with its position and orientation related to the robot's base frames or predefined user frame. The robot will move from point to point using the desired motion type (linear, arc, or joint).The trajectory planning requires first to check if robot can reach the selected part(s). This can be simply done by placing the part(s) inside the robot's work envelope. The robot's work envelope represents a set of all robots' reachable points without considering their orientation. To visualize the robot's work envelope many available tools can be used.It is common that some of the accessible points cannot be reached with the desired tool orientation. For accurate and optimal robot path generation, a visualization of the predetermined regions related to the application is highly needed. These regions are named robot work window.In this paper, the work window has been calculated for the Fanuc LR Mate 200ic robot and the rapid prototyping application. The visual representation of the work window has been done using MATLAB tools and evaluated using the Fanuc LR Mate 200ic robot which is available in our lab.