In the VR tutorial, how to set the camera window with blue and yellow borders?

Is a rendering security box, and cannot be rendered out of range. The rendering security box allows you to know your picture composition before you start rendering, so that you can adjust it in advance. The security box comes with 3D, which can be opened under the picture selection. Try to enter the camera! This is hard knowledge, read it well, it doesn't need the guidance of others! !