User Guide > Overview > Objects   

Creating a Camera

You create cameras at the object level using the Camera tool. Press the tab key and start typing camera then press Enter. Next, RMB-click to place the camera which appears with its interactive handles ready. These handles let you position the camera and set up clipping planes and focus distance. They can also be used to preview which objects are visible from the camera using the frustum clipping option.

Editing the Camera - Later when you want to edit the camera using these handles, you can either select it using the Object tool which invokes the camera handles or select it with the Transform tool which uses the transform handles then press enter to change to the camera handles.

Topics covered:
Camera Orientation handles
Camera Frustum handles
Camera Focus handles
Frustum Clipping
Other Camera Properties


Camera Orientation Handles

The default camera handle is the orientation handle. As you begin working with other handles, you can return to this handle by either RMB-clicking on the handle and selecting Orientation Handle, or pressing the o key. This handle lets you control the eye point and look-at point to position the camera.

The orientation handle is made up of transform handles and rotation handles. The transform handles move either the look-at or eye point based on the camera's local axes. This means that the handle will move perpendicular or tangential to the arc that runs between the two ends of the handle. The rotate handles let you move along the arc that runs between the two ends. If you click on either of the rotate handles then moving the opposite position handle will move both ends of the camera setup instead of only the one end.

Tip: The camera's look-at handle is a camera controls the rotation parameters on the camera. If you want a separate look-at control then you will need to create a Null object and apply this to the camera's Look-At attribute. This separate null object can be keyframed on its own or parented into another object hierarchy. You can also control the camera's Look-At Up Vector using the same concept.


Camera Focus Handles

To work with the Camera Focus handle, RMB-click on the handle and select Focus Handle, or press the z key. This handle lets you control the camera's Focus and F-stop parameters. These parameters are used to help set up a depth of field rendering. These handles are very effective when used with frustum clipping.


Camera Frustum Handles

To work with the Camera Frustum handle, RMB-click on the handle and select Frustum Handle, or press the f key. This handle lets you control the camera's Near and Far clipping planes and the camera's Focal length.

Tip: The aspect ratio of the frustum can be set using the Resolution parameter found under the camera's View tab in the Parameter pane.


Frustum Clipping

To help you visualize what objects are visible in the camera, you can use Frustum clipping with a shaded scene. To turn on this feature, RMB-click on the camera handle and select one of the following clipping options:

Full Frustum Clipping. This clipping option uses the near and far clipping planes along with the walls of the frustum to limit which parts of your scene are shaded. Any objects seen inside the frustum are shaded and show you what will be seen in the camera.

Tip: If you want to keep this clipping while you position objects in the camera's view, RMB-click on the handle and turn Persistent on. Now even if you deselect the camera the clipping will still take place. Now as you move objects around the scene, you can preview when they are leaving the camera's view. Note that if you make more than one camera persistent then the shaded results will be unpredictible.

Focus Frustum Clipping - This option uses the Focus and F-stop attributes to preview which objects will appear in focus when you render the camera's depth of field. The two bounding arrows represent the point where the rendering will be blurred twice as much as the focal point.


Other Camera Properties

In the Parameter pane, a camera has several tabs that offer different camera properties:

View - This tab contains several parameters that are controlled by the camera handles and a few that are not. This is where you can set the render Resolution, which in turn sets the frustum's aspect ratio. You can override this value with a Render Operator.

You can also set the Pixel Aspect ratio for working with digital video and the Shutter speed for working with depth of field.

Cameras also have a Lens Curvature setting for simulating realistic lens effects such as a fish eye lens. Note that this option will turn off micropolygon rendering in Mantra and should be used carefully.

Crop - These parameters let you focus on a smaller portion of the camera view. You can also rotate the camera around the line of sight.

Roto - This tab lets you set up a background clip for rotoscoping. An important tool when integrating live action and CG elements.