Motivation

The primary use case is recording videos, images, and screen outputs, using the Timeline. There’s also a secondary use: switching the screen view to a specific region, either manually (right-click in the Workspace and select “Set Active Camera…”) or during recording and playback (see Timeline Screen Camera Track).

Cameras address these situations:

• Every model has interesting regions requiring detailed observation, and mundane regions where pedestrians simply transit between objectives.
  • Outputs should precisely focus on the interesting regions, while maximally excluding the mundane regions.
    • For example, regions of congestion or pedestrian interchange (e.g., blue boxes) usually require targeted analysis, while mundane thoroughfare regions (e.g., orange boxes) need less analysis (or none).

• Capturing the entirety of a large model can obscure finer details in recorded outputs.
  • Details are important and should be captured with sufficient clarity.
    • For example, the left image shows the entire model and lacks observable detail, e.g., around the ticket gates (blue box). The image on the right covers just the ticket gates and shows greater detail.

• Pixel dimensions of the LEGION workspace may not align with desired output dimensions, especially when graphs and map legends are visible.
  • Outputs should be independent of workspace dimensions.
    • For example, a standard image or video output dimension is 1920 x 1080 pixels, so it fits neatly on 16:9 full HD display. Yet, in the LEGION workspace view below (blue box) the workspace is clearly not this size or aspect ratio (in fact it’s 1429 x 449 pixels, an approximate 3.18:1 ratio; not friendly dimensions for video or images).

• Consistency of outputs. It is helpful for all outputs to have a similar arrangement, as this makes for easier viewing and consumption by stakeholders.

LEGION Simulator supports unlimited Cameras. Camera boundaries may overlap.

Output and Visualisations Which Depend on Cameras

These outputs and visualisations depend on Cameras:

• Recording an AVI using the Timeline.
• Saving a Map Image using the Timeline.
• Activating a Screen Camera using the Timeline.
• Setting the current view to a specific Camera.

LEGION Camera Concepts

• Whole Model Camera: A system-defined Camera that encompasses the entire model area and automatically updates to model content changes. The aspect ratio for this Camera can be modified, but the Field of View cannot.
  • All LEGION Simulator projects include this Camera (it is added to upgraded projects).
• Camera Coverage: The area inside the Camera boundary, which is based on two related parameters:
  • Field of View: The X and Y dimensions of the actual model region within the Camera boundary. These define the size (and shape) of the Camera:
    • Field of View is always in the active unit system (metric or imperial).
    • The minimum permitted Field of View is 1m x 1m (or 3.29ft x 3.29ft).
    • The maximum permitted Field of View is the size of the Whole Model Camera
  • Aspect ratio: The ratio of Field of View width to height, which defines the shape of the Camera (but not the size).
    • Aspect Ratio is unitless (e.g., 16:9, 21:9, 4:3).
• Maintaining Aspect Ratio: When a Camera’s aspect ratio stays constant while its Field of View is modified. The size changes but the shape does not. Changing one Field of View dimension automatically updates the other, the aspect ratio does not change.
• Centre Lock: The Camera’s centre point does not change when its aspect ratio or Field of View is modified. Keeps the Camera focussed on the interesting region while its size and/or shape is modified.