Cameras

17

Cameras

Cameras are objects that you use to view a scene. A modeling window represents the view from a camera. This view is used to create an image of your scene during rendering.

In This Section:

• Camera Overview 324
• Using Cameras 327
• Using Image Planes 330
• Camera Editor 333
• Camera Parameters 334
• Image Plane Properties 345

Camera Overview

A camera represents a particular view of your scene. By changing the position and orientation of a camera, and the properties of the camera's lens and film, you can control the camera's view.

A modeling window represents the view of a particular camera. Each modeling window has an associated camera, but each camera does not necessarily need to have an associated modeling window.

There are two types of cameras: orthographic and perspective. The view from an orthographic camera does not include the effect of perspective. That is, an object will appear the same size no matter how far it is from the camera. The view from a perspective camera includes this effect; an object will appear larger when it is close to the camera, and smaller when it is far from the camera.

A single scene may contain several cameras. For example, by default a scene contains four cameras corresponding to the four modeling windows: top, front, right, and perspective (camera). You can render the view from one or several of the cameras in a scene.

In some cases a modeling window may not represent the exact view of a camera. For example, if the aspect ratio of the film back does not match the aspect ratio of the camera's modeling window, then the window will only show a portion of the camera's view (see Film Back Properties on page 335). Another example is the magnify window which represents a magnified view of a modeling window (see Magnify in the Basic Tools in Alias book).

A perspective camera appears in the SBD and ASBD windows as a group of nodes representing the camera's position (eye point), view (look at point), and up point. You can also display perspective cameras in the orthographic modeling windows as a green icon. Orthographic cameras do not appear in the SBD and ASBD windows unless the camera has an image plane.

Image Planes

An image plane is an image that you can attach to a camera's view. This image appears in the camera's modeling window and in images rendered from that camera (either in front of or behind the scene). Any camera can have one or several image planes. For example, you could use an image plane as a visual reference when building a model, or as a background for your scene when rendering.

An image plane appears in the SBD and ASBD windows beneath the camera's eye node. This it is not a hierarchical grouping, however. Any transformations you make above the eye node do not affect the image plane. If you add an image plane to an orthographic camera, the orthographic camera appears in the SBD and ASBD windows with the image plane beneath its eye node.

Using Cameras

You use cameras to generate views for modeling windows and to generate views to render.

Creating or Copying a Camera

You can create a new camera by selecting Layouts > New camera (see Creating New Windows in the Basic Tools in Alias book). You can copy an existing camera using the Clone tool (see Cloning the Current Window in the Basic Tools in Alias book).

Displaying Camera Icons

You can control whether camera icons are displayed in the orthographic modeling windows by selecting DisplayTgls > Object Toggles > Camera (see Changing the Display of Cameras in the Basic Tools in Alias book).

Changing a Camera's View

You can change a camera's view by changing its Camera Properties, Film Back Properties, and Lens Properties. (see Camera Properties on page 334, Film Back Properties on page 335, and Lens Properties on page 338). You can also change a camera's view using the camera tools (see Using Cameras in the Basic Tools in Alias book), or the modeling window control icons (see Modeling Window Control Icons in the Basic Tools in Alias book).

Zoom and Dolly

Both zooming and dollying change the size of all objects in your scene as they appear in the camera's window. Dollying, however, also changes the size of objects that are near the camera relative to objects that are far from the camera. Zooming maintains the relative size of objects in your scene.

Track and Film Back Offset

Both tracking and changing the film back offset value change the position of all objects in your scene as they appear in the camera's window. Tracking, however, also changes the position of objects that are near the camera relative to objects that are far from the camera. Changing the film back offset value maintains the relative position of objects in your scene.

Animating a Camera

You can animate a camera parameter setting in the Camera Editor by Shift-clicking the name of the parameter, and then clicking the Key button in the title bar of the Camera Editor. This is similar to the procedure for animating parameter settings in the Control Window (see Animating Parameter Settings on page 40). You can also animate a camera using Animation > Turntable, Animation > Autofly, or Animation > Set keyframe (see in the Animating in Alias book).

Selecting Camera Views to Render

You can select which camera views will render an image file, mask file, or depth file in the Render Globals window.

To select which camera views will render:

See Render Globals Window on page 396.

1

Select Render > Globals to open the Render Globals window.

See Image File Output on page 411.

2

In the Image File Output section of the Render Globals window, set the Image toggle on for the camera views you want to render as images. By default, only perspective cameras have their Image toggle on. You can also set the Mask and Depth toggles to select which camera views will render as mask files or depth files.

A camera will not render an image file, mask file, or depth file if the camera is invisible, regardless of its Image, Mask, and Depth toggle settings.

Using Image Planes

You use image planes as visual references while building a model, or as a means of compositing background and/or foreground images during rendering.

Adding or Deleting an Image Plane

You can add any number of image planes to a camera.

To add an image plane to a camera using Import Image Plane:

1

Select the modeling window of the camera you want to add an image plane to.

See Importing Image Planes in the Basic Tools in Alias book.

2

Select File > Import > Image plane to open the File Requestor.

3

Use the File Requestor to select the image file you want to use as an image plane, and click Load Image.

The image plane appears in the modeling window.

To add an image plane to a camera using the Camera Editor:

See Camera Editor on page 333.

1

Select Windows > Edit > Cameras to open the Camera Editor.

See Camera on page 334.

2

At the top of the Camera Editor, set Camera to the camera you want to add an image plane to.

See Add on page 345.

3

In the Image Planes section of the Camera Editor, click the Add button to open the File Requestor.

4

Use the File Requestor to select the image file you want to use as an image plane, and click Load Image.

The image plane appears in the modeling window, and an image plane swatch appears in the Image Planes section of the Camera Editor.

To delete all image planes from a camera:

1

Select the modeling window of the camera you want to delete all image planes from.

See Deleting Image Planes in the Basic Tools in Alias book.

2

Select Delete > Del image planes to open the Delete Image Plane Options box.

See Delete Image Plane Options in the Basic Tools in Alias book.

3

In the Delete Image Plane Options box, set Delete Type to Current Window, and click Go.

All image planes are deleted from the active window.

To delete one image plane from a camera:

See Camera Editor on page 333.

1

Select Windows > Edit > Cameras to open the Camera Editor.

See Camera on page 334.

2

At the top of the Camera Editor, set Camera to the camera you want to delete an image plane from.

See Delete on page 345.

3

In the Image Planes section of the Camera Editor, select the swatch of the image plane you want to delete, and click the Delete button.

The image plane is deleted from the camera's window, and from the image plane swatch list in the Image Planes section of the Camera Editor.

Animating an Image Plane

You can animate an image plane using a variety of different methods:

• Animate an image plane parameter setting in the Camera Editor by Shift-clicking the name of the parameter, and then clicking the Key button in the title bar of the Camera Editor. This is similar to the procedure for animating parameter settings in the Control Window (see Animating Parameter Settings on page 40).

• Use a series of images as an animated image plane by setting the Frame Type parameter in the Image section of the Camera Editor (see Frame Type on page 348).

• Use Animation > Set keyframe (see Setting Keyframe Animation in the Animating in Alias book).

Sizing and Positioning an Image Plane

By default, an image plane fills the camera view with the entire image. You can size and position an image plane so that only a portion of the image appears or so the image appears in a specific region of the camera view. Use the Image Placement parameters in the Camera Editor to size and position an image plane (see Image Placement on page 353).

Masking an Image Plane

You can mask an image plane so that only portions of the image are visible. Use the Mask parameters in the Camera Editor to mask an image plane (see Mask on page 350).

Camera Editor

The Camera Editor is the primary interface that you use to edit cameras and image planes.

Camera Editor parameters behave similarly to Control Window parameters (see Parameters on page 35).

The Camera Editor contains parameters which control the properties of cameras and image planes. The title bar of the Camera Editor contains a keyframe button which lets you set a keyframe for a parameter, and a model pick button which lets you select the modeling window associated with the current camera in the Camera Editor.

To open the Camera Editor:

1

Select the modeling window corresponding to the camera you want to edit.

2

Select Windows \> Edit \> Cameras.

See the next sections for details on the parameters available in this window:

• Camera Parameters on page 334

• Image Plane Properties on page 345