一种实现VRML中坐标变换的方法

针对各VRML造型在其局部坐标系中创建，采用变换矩阵实现了造型从局部坐标系下到世界坐标系下的坐标变换。首先假设出每次坐标变换对应的矩阵，用对应矩阵的逆、乘积运算表示出一个点经过多次坐标变换的变换公式。然后根据VRML坐标变换按照缩放、旋转、平移的顺序进行，推导出一次坐标变换的步骤。通过将Transform节点各域的域值参数化，推导出对应各域的参数矩阵，进而推导出一次坐标变换的参数矩阵表示。最后使用IndexedFaceSet节点，利用Cosmos Player浏览器和MATLAB两种工具，对结论进行了验证。

Realization of coordinate transform in VRML

Because each model in VRML is created in local coordinate system,inconvenient to handle them uniformly,this paper infers a universal formula to transform model coordinates from UCS to WCS.First infers total formula with each coordinate transform matrix,then proposes one coordinate transform steps based on process of scale,rotation,translation in VRML.By parameterizing the field values of Transform in VRML,this paper gives parameterized matrix corresponding to each field and finally infers parameterized matrix corresponding to one coordinate transform.At last to test the conclusion this paper creates some models with IndexedFaceSet using Cosmos Player Viewer and MATLAB.