Creating a Camera 

The camera enables you to specify a viewpoint from which a photorealistic image will be computed. This task shows you how to create a camera and manage its specifications.
  Note that some of the adjustments detailed in this scenario can also be performed using the Camera Commands toolbar.
Open the Lamp.CATProduct document.
  1. Click Create Camera . The camera is created at the current viewpoint.

  2. Click the Camera item in the specification tree and rotate the model to see the camera symbol:

    This standard visualization is not affected by any change of scale ("zoom").

    In case you wish to hide the camera representation, right-click the camera in the specification tree then select Camera object > Hide/Show Representation. Inversely, this command lets you show a hidden representation.

    You can create several cameras at different locations to have different viewpoints.
    The camera which is taken into account to render a given image is said to be active. Any other camera is inactive.
  3. Use the two spheres and the two squares displayed in green on the 3D representation to interactively manipulate and position the camera.

    This visualization is affected by changes of view scale (zoom) and is activated when selecting a camera in the scene or in the specification tree. Otherwise, all elements are set to the standard visualization.

    Conical camera

    Pyramid height = focal length 
    Pyramid base = film dimensions

    Cylindrical camera

    Plane = film dimensions


    • the source point (1) rotates the camera around its target point
    • the target point (2) rotates the camera around its source point
    • the source green square translates and rotates the camera around its target point
    • the target green square translates and rotates the camera around its source point.

    Cameras are needed to render and view a scene. "An image is worth a thousand words": the better the camera is positioned, the more accurate the saying.

  4. Select the camera in the specification tree then right-click and select Properties (or press Alt+Enter). The Properties dialog box is displayed:

  5. In the Lens tab, select the lens type: Perspective or Parallel, i.e. to obtain a conical or a cylindrical projection. The Preview area shows the result of your selection accordingly.

    A conical camera is equivalent to a standard camera, with a non-zero focal length. 
    Parallel lines in the camera line of view appear to intersect at the same point.
    Perspective cameras are used in most cases since they are close to the human vision.

    In the case of a cylindrical camera, parallel lines never appear as intersecting.
    These cameras are mainly used to define architectural viewpoints.

  6. Specify the Focal Length, which determines the field of view, in millimeters.
    The focal length is the distance between the camera origin and the viewing plane.

    In a cylindrical projection, the focal length is replaced by a zoom factor which determines the scale of view (i.e. Scale appears instead of Focal Length in the dialog box).
    You can also specify the camera view directly inside the preview window by zooming, rotating or panning the view:
  7. Click the Position tab to define the target and origin position.

    You can define the Origin and the Target position in millimeters along the X, Y and Z axes.

    If you are not satisfied with the values you defined, you can click the Reset value button next to the desired parameter to reset its value.

    The Feature Properties tab provides general information on the currently selected camera, e.g. its name, its creation date, etc.
    Snapping the compass to the camera lets you modify the camera position and orientation very easily simply by dragging the arcs of the compass as shown below:
    For detailed information about compass manipulation, refer to "Moving Objects Using the 3D Compass" in the Version 5 - Infrastructure User`s Guide.
  8. Select the Update camera from View check box to adjust (i.e. center) automatically the camera whenever the viewpoint is modified:

    This avoids using the Update from View contextual command each time a viewpoint modification is done.
  9. Click OK when finished.

  10. If you want to position yourself behind the camera and observe the captured image, select Window > Camera Window: a new window displaying the camera viewpoint is opened. When you manipulate the handler in this window, the camera is simultaneously positioned in the main window.

    You can choose three arrangements for the opened windows, i.e. horizontal, vertical and cascading by selecting the following commands from the menu bar:

    • Window > Tile Horizontally
    • Window > Tile Vertically
    • Window > Cascade
    Example of vertical tiling
  11. To close the camera window, you can either click the cross in the top-right corner of the window or reselect Window > Camera Window > Camera x.

You can double-click the Camera item in the specification tree to position the camera from the current point of view.

You can also right-click the camera in the specification tree then select Update From View to update the camera when the viewpoint is modified.