As the modeling of the solar system is difficult and inaccurate, the 3D modeling of the planets in the solar system is studied by using Java3D technology. To make the revolution of simulated planets meet Kepler's laws while traveling around the sun, an improved approximate algorithm to calculate the optimum angle and the vertex coordinates of each planet is proposed. Using java3D perspective projection technique, the observation coordinate system is determined, and real-time viewpoint setting as well as roaming processing is realized. Through multiple view technique, we can observe the movement of celestial bodies from multiple aspects to obtain vivid simulation effects of planets' behavior in the solar system. Simulation results show that the virtual simulation platform developed based on java3D can improve the accuracy and naturalness of solar system simulation.

During the design and manufacture of hydraulic system, valve block of processing is time-consuming and labor-intensive, and its easy to make a mistake. In this paper, a simple numerical control system based on PLC control to solve the practical engineering problem is studied. An automatic positioning based on parameters of holes which are drawn by AutoCAD and an automatic machining of holes can be realized by the control system. Its also discussed that the method and process of the design of software and hardware.