Design and Implementation of a 3D Dynamic Geometric Global Coordinate System

The three-dimensional dynamic geometry system (3D DGS) can intuitively present three-dimensional spatial and is widely used in solid geometry teaching. The design and implementation of the coordinate system in three-dimensional space is its essential foundation. The coordinate system of the existing 3D DGS can’t be moved, rotated, zoomed, which make the DGS not meet teaching needs. In this paper, we analyze the transformation requirements and the design goal of the coordinate system. And we propose a method of the coordinate transformation of DGS and introduce the transformation process among the pixel coordinate system, the image coordinate system, the camera coordinate system and the world coordinate system. Based on the above coordinate transformation method, the movement, rotation, and zoom of the coordinate system are implemented in NetPad 3D. Finally, the comparison of a teaching case demonstrates that users develop resources conveniently with NetPad 3D.