3D直接操作的自动视图控制

Automatic Viewing Control for 3D Direct Manipulation

阐述通过自动寻找虚拟相机的有效位置以增强3D直接操作过程的技术。当前许多直接操作3D几何形体的尖端技术都强烈地依赖于视角,因此需要用户在操作过程中确定视点的坐标。在某些情形下,这个过程可以自动化。这意味着系统可以自动避免退化位置,而在退化情形,平移与旋转操作是难以实现的。系统还能选择视点和视角,使得被操作的物体可见,确保不被其他物体遮挡。

This paper describes a technique for augmenting the process of 3D direct manipulation hy automatically finding an effective placement for the virtual camera. Many of the best techniques for direct manipulation of 3D geometric objects are sensitive to the angle of view, and can thus require that the user coordinate the placement of the viewpoint during the manipulation process. In some cases, this process can be automated. This means that the system can automatically avoid degenerate situations in which translations and rotations are difficult to perform. The system can also select viewpoints and viewing angles which make the object being manipulated visible, ensuring that it is not obstructed by other objects.