获得三维模型指定点的空间坐标是针对模型文件操作的基础。针对传统算法的不足提出一种获取所选点原始坐标的方法。在选点的过程中, 该算法允许模型进行任意角度的旋转, 以选取模型侧面及背面的点, 并通过旋转矩阵对该点还原。算法完成从屏幕的二维像素坐标到模型的三维坐标, 再到模型文件原始坐标的转换。实验表明, 该方法可以准确获取模型的所有可视表面的点坐标,提高了拾取的灵活性。

To pick-up a specified coordinate of a point is a basic operation for a 3D model file. Aimed at the shortages of traditional methods about 3D picking, a new method, which points at getting the original coordinate of specified point, is proposed.During picking, rotation at any angle is allowed. So points either on the side or on the back can be selected.And rotation matrix is used to restore points to their original state.The method transform the two-dimensional pixel coordinate to 3D model coordinate then to original model coordinate. All the points on visible surface can be picked precisely by this method and thus the flexibility is improved.