# Visual Cone

This task describes the movement of the eyes of a Manikin.

### Line of Sight

In order to reproduce the human vision with more accuracy, in this new vision model, the camera doesn't follow the line of sight orientation anymore.  In other words, the central spot (which corresponds to the line of sight) moves inside the Vision Window following the eyes motion.
With this new vision model, we realized that it was very important to make a clear distinction between field of view and Vision Cone.

Field Of View:

The field of view is the limit of what can be seen by the manikin.  This zone is delimited vertically and horizontally by motionless obstacles around the eyes (eyebrows, cheeks and nose) as illustrated:

So, when somebody is looking down, the resulting field of view (visual field) orientation remains the same because the obstacles around the eyes don't move with the eyes.  This is true until the eyes arrive at the limit of the eye "intrinsic field of view".  But, this scenario is not taken into account in the vision model.

The vision cone is an arbitrary limit that can be specified in order to analyze what can be seen by the manikin inside a certain degree around the line of sight.  This limit can represent an optical characteristic of the eye, like the limit for maximum acuity (approximately 1 degree) or the limit for colors discrimination (around 35 degrees). Previously, with this new vision paradigm is that the circle representing the central cone always kept the same shape no matter its position in the vision window (3D viewer) whereas all the objects at the periphery of the viewer was naturally deformed. To solve this problem, there is a 3D circle in the surface of the Visual Cone.

1. Select Vision from the Manikin Tools toolbar and then select a manikin, OR  double-click on the Manikin > Profiles > Vision node to achieve the same results.

2. The default vision window appears.

No vision window will appear until the manikin is selected.

3. With the display of the central spot will be fixed at 3 degrees.  This point is named Focal Point (instead of Central spot) and will no longer be adjustable.  It represents only the target of the line of sight.

To see the Line of Sight and the Visual Cone in the Display panel.

4. In the toolbar, select the Forward Kinematics , and select the Visual Cone.
Note that this icon must be unselected by clicking on it again in order to access another function.

5. Right-click the Visual cone by clicking it with the left mouse button to get the contextual menu.

6. When you move the line of sight, the shape of the Visual Cone representation (in the vision window) will be altered (yellow circle), just as is the case with other objects.