Though the picture ratio is preset for each standard, the value is not locked. If you accidentally change the picture ratio value, the standard will change to Custom automatically.
The Camera Property Editor [Properties Reference] contains every parameter needed to define how a camera “sees” your scene.
To open the camera property editor
• Do one of the following:
- Select a camera whose properties you want to edit and choose Modify > Shader from the Render toolbar.
- Click on the camera’s icon in the explorer.
- Double-click the camera’s node in the render tree.
- From the camera icon menu of any viewport set to the camera’s view, choose Properties.
The camera’s “format” refers to the picture standard that the camera is using and the corresponding picture ratio. You can also specify a custom picture standard with a picture ratio that you define. The default camera format is NTSC D1 4/3 720x486, with a picture ratio of 1.333, but several standard NTSC, PAL, HDTV, Cine, and Slide formats are also available.
To set the camera format
1. Select a camera from a viewport and choose Modify > Shader from the Render toolbar. The selected camera’s property editor opens.
2. From the Primitive tab, choose a picture standard from the Standard list. If you select Custom, you must then set the Pict. Ratio value.
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Though the picture ratio is preset for each standard, the value is not locked. If you accidentally change the picture ratio value, the standard will change to Custom automatically. |
The field of view is the angular measurement of how much the camera can see at any one time. By changing the field of view, you can distort the perspective to give a narrow, peephole effect or a wide, fish-eye effect.
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Field of View settings have no effect on orthographic cameras. Instead, you can adjust the Ortho Height parameter to include more or less of the scene in the camera’s view. |
To set the field of view
1. Select a camera from a 3D view and choose Modify > Shader from the Render toolbar. The selected camera’s property editor opens.
2. In the Field of View section, select whether you want to specify the Vertical or Horizontal field of view. Softimage calculates the other dimension using the aspect ratio.
3. Set Angle to the desired value in degrees.
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Each camera projection type has its own default field of view. For example, a wide-angle projection has a large field of view, whereas a telephoto camera has a smaller field of view. You can edit these cameras’ fields of view at any time. |
The formulas to determine your horizontal or vertical Field of View are as follows:
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Horizontal FOV |
w = film width in mm (e.g., 36) (= h * aspect ratio) d = lens focal distance in mm (e.g., 50) Horizontal FOV = 2 * atan( ( 0.5 * w ) / d ) |
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Vertical FOV |
h = film height in mm (e.g., 24) (= w / aspect ratio) d = lens focal distance in mm (e.g., 50 Vertical FOV = 2 * atan( ( 0.5 * h ) / d ) |
You can easily change any camera from an orthographic to a perspective projection.
To select a projection
1. Select a camera from a 3D view.
2. Choose Modify > Shader from the Render toolbar. The selected camera’s property editor opens.
3. In the property editor, you can select one of two projection methods:
- Orthographic: all camera rays are parallel and objects do not change size as they change distance from the camera. This projection is useful for architectural and engineering renderings.
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Field of View settings have no effect on orthographic cameras. Instead, you can adjust the Ortho Height parameter to include more or less of the scene in the camera’s view. |
- (Default) Perspective: the projection simulates depth. This projection is useful for simulating a physical camera.
You can use clipping planes to set the minimum and maximum viewable distances from the camera. Objects outside these planes are not visible.
By default, the near plane is very close to the camera and the far plane is very far away, so most objects are usually visible. You can set clipping planes to display or hide specific objects.
To set clipping planes
1. Determine the acceptable minimum and maximum distances from the camera.
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To help determine what distances are acceptable within a scene, click the eye icon in the viewport and choose Distance to Output Camera. The distance is displayed in Softimage units. |
2. Select a camera and display its property editor by choosing Modify > Shader from the Render toolbar.
3. Set the Near Plane and Far Plane values according to your near and far distance calculations.
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• You can sometimes reduce rendering time by choosing appropriate clipping planes. By default, the near clipping plane is very close to the camera and the far clipping plane is far away. However, if an image contains distant, complex objects, you may want to set the far clipping plane so that these objects are not rendered. • You can also enhance the depth precision (or resolution) displayed in the OpenGL views if you make the near and far clipping planes closer to your objects. For more information on how to set OGL view options, see Image Clip OGL Display Settings [Texturing]. |
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Clipping planes have no effect when scanline rendering is not activated. For information about activating scanline rendering, see Choosing a Rendering Algorithm [Rendering]. |
Setting up a camera using the options on the Primitive tab allows you to control how much of the scene the camera sees by adjusting the field of view (see Setting the Field of View). However, this is sometimes not sufficient to configure the camera properly—particularly when you need to match a virtual camera to a real-world camera’s specifications.
For example, real world cameras have lenses that are mounted offset from the center of the image plane, so that the apex of the viewing “frustum” is offset from the center of the rendered image. On many cameras the lens offset—called shift—is adjustable and allows you to reposition the lens while keeping the camera body, and thus the film plane, fixed. Lens shift is often used for architectural photography because it can help correct perspective distortion or even maintain perspective while changing the composition of the picture.
Also, a real world camera's field of view is a function of both the lens' “focal length” (55mm, 85mm, 135mm, “wide-angle”, “telephoto”, and so on) and the dimensions of the area onto which an image is projected by the lens. Different types of cameras all have characteristic image area dimensions that vary not only from one product to another, but from one camera to another, because of inaccuracies in the manufacture of mechanical, optical, and electronic components (film gates, CCDs, etc.).
To help you match the virtual cameras in your scene to real world cameras, you can use the projection plane controls to adjust the field of view more precisely and replicate lens offsets.
To set the camera’s projection plane
1. Select the camera whose projection plane you want to adjust and display its property editor by choosing Modify > Shader from the Render toolbar.
2. From the Projection Plane tab, enable the projection plane.
3. To set the camera’s plane’s field of view, use the following options:
- Focal Length (mm) specifies the camera’s focal length in millimeters.
- Film Aperture (inches) specifies the width and height of the area of the film’s image area, in inches.
- Lock Aspect Ratio, when enabled, preserves the film’s aspect ratio. Disabling this option allows you to change the film’s aspect ratio by adjusting the X or Y value.
4. If necessary, adjust the Optical Center Shift (inches) value to offset the camera’s lens from the center of the image by the specified distance.
5. If necessary, you can reset the projection plane values to match the camera values by clicking the Align button.
Autodesk Softimage v.7.5