Defining field of view for the ray tracings.
The fields of view (that is, screen limits) defined by the user will be used for the pictures that appears on the screen during the ray tracings (that is, the rz view for CPO2D or the xy, yz and zx views for CPO3D).
The screen limits do not have to have the same span (that is, maximum-minimum). In other words the aspect ratio does not have to be 1:1 -in fact users normally make it very different from this. The aspect ratio can of course be changed at the interactive stage.
To let the program decide the field of view, make at least one of the spans zero or negative (for example by making all the limits zero). The program will add a 5% margin to the picture.
To obtain a full view at the end of a run, click on ‘unzoom’