The plane defined by the 3 points should never get close to being parallel with the camera plane (normally a vertical plane) when pitching downward, otherwise the tracking directions reverse. This can be avoided by moving the model's middle point further back and/or reducing its height.
没人顶，继续补充：
The model dimensions need to be entered in millimetres and must reflect the default position of the model. The horizontal and vertical directions measured should be parallel to the camera's horizontal and vertical. Click the Apply button for the newly entered model dimensions to take effect.
发表于 2011-10-3 13:59:23