When the spatial constraints are taken into account, the problem about dispatch and optimization of block erection in shipbuilding becomes more complicated. A human-machine interaction approach is proposed and extended to quickly find an approximate optimal solution. First, a steer genetic algorithm enables users to guide the computing to an effective iterative direction and leverages the computing. The model of block erection dispatch to the crane is a parallel machine scheduling problem with spatial constraints. The genetic crossover operators can be guided according to the activities of block erection in shipbuilding. Two criteria are presented to justify the effectiveness of the proposed algorithm and a fitness function is given to represent the makespan. Moreover, three-dimensional spatial constraints, which affect the parallel machine scheduling problem heavily, are visualized. A better erection path can be obtained dynamically, when the users are in an immersive environment. Finally, a three-dimensional layout prototype system of block erection is developed with real size, embedded with an interactive genetic algorithm optimization to solve this problem with the objective of minimizing makespan.