Define an AOI as a frame
========================




## Add ArFrame to ArUcoScene

The [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame) class defines a rectangular area where timestamped gaze positions are projected in and inside which they need to be analyzed. An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) instance can contains multiples [ArFrames](../../argaze.md/#argaze.ArFeatures.ArFrame).

Here is the previous extract where the "GrayRectangle" AOI is defined as a frame into the [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) configuration:

```json
{
    "name": "My FullHD camera",
    "size": [1920, 1080],
    ...
    "scenes": {
        "MyScene" : {
            "aruco_markers_group": {
                ...
            },
            "layers": {
                "MyLayer": {
                    "aoi_scene": {
                        "YellowSquare": [[6.2, -7.275252, 25.246159], [31.2, -7.275252, 25.246159], [31.2, 1.275252, 1.753843], [6.2, 1.275252, 1.753843]],
                        "GrayRectangle": [[2.5, 2.5, -0.5], [37.5, 2.5, -0.5], [37.5, 27.5, -0.5], [2.5, 27.5, -0.5]]
                    }
                }
            },
            "frames": {
            	"GrayRectangle": {
            		"size": [350, 250],
            		"layers": {
            			"MyLayer": {
            				"aoi_scene": {
            					"BlueTriangle": [[100, 50], [250, 50], [175, 200]]
            				}
            			}
            		}
            	}
            }
        }
    }
    ...
}
```
Now, let's understand the meaning of each JSON entry.

### "GrayRectangle"

The name of the AOI and the [ArFrame](../../argaze.md/#argaze.ArFeatures.ArFrame). Basically useful for visualisation purpose.

!!! warning "Frame name policy"

    An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layer AOI is defined as an [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frame, **provided they have the same name**.

!!! warning "Layer name policy"

    An [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frame layer is projected into [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layer, **provided they have the same name**.

!!! note

    [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) frame layers are projected into their dedicated [ArUcoScene](../../argaze.md/#argaze.ArUcoMarkers.ArUcoScene) layers when the JSON configuration file is loaded.