Learning to Work with Cameras in 3D max

If you’re a photography hobbyist or like to take your video camera out and shoot your own footage, then many of the terms in this section will be familiar to you. The cameras used in Max to get custom views of a scene behave in many respects just like real-world cameras.

Max and real-world cameras both work with different lens settings, which are measured and defined in millimeters. You can select from a variety of preset stock lenses, including 35mm, 80mm, and even 200mm. Max cameras also offer complete control over the camera’s focal length, field of view, and perspective for wide-angle or telephoto shots. The big difference is that you never have to worry about focusing a lens, setting flashes, or loading film.

Light coming into a camera is bent through the camera lens and focused on the film, where the image is captured. The distance between the film and the lens is known as the focal length. This distance is measured in millimeters, and you can change it by switching to a different lens. On a camera that shoots 35mm film, a lens with a focal length of 50mm produces a view similar to what your eyes would see. A lens with a focal length less than 50mm is known as a wide-angle lens because it displays a wider view of the scene. A lens longer than 50mm is called a telephoto lens because it has the ability to give a closer view of objects for more detail, as a telescope does.

Field of view is directly related to focal length and is a measurement of how much of the scene is visible. It is measured in degrees. The shorter the focal length, the wider the field of view. When we look at a scene, objects appear larger if they are up close than they would be lying at a farther distance. This effect is referred to as perspective and helps us to interpret dis- tances. As mentioned, a 50mm lens gives a perspective similar to what our eyes give. Images taken with a wide field of view look distorted because the effect of perspective is increased.

Creating a camera object

To create a camera object, you can use the Create➪Cameras menu, or you can open the familiar Create panel and click the Cameras category button. The two types of cameras that you can create are a Free camera and a Target camera.

Camera objects are visible as icons in the viewports, but they aren’t rendered. The camera icon looks like a box with a smaller box in front of it, which represents the lens or front end of the camera. Both the Free and Target camera types can include a cone that shows where the camera is pointing.

Free camera

The Free camera object offers a view of the area that is directly in front of the camera and is the better choice if the camera will be animated. When a Free camera is initially created, it points at the negative Z-axis of the active viewport. The single parameter for Free cameras defines a Target Distance—the distance to an invisible target about which the camera can orbit.

Target camera

A Target camera always points at a controllable target point some distance in front of the camera. Target cameras are easy to aim and are useful for situations where the camera won’t move. To create this type of camera, click a viewport to position the camera and drag to the location of its target. The target can be named along with the camera. When a target is created, Max automatically names the target by attaching “.target” to the end of the camera name. You can change this default name by typing a different name in the Name field.

Creating a camera view

You can change any viewport to show a camera’s viewpoint. To do so, right-click the viewport’s title, and select View and the camera’s name from the pop-up menu. Any movements done to the camera are reflected immediately in the viewport.

Another way to select a camera for a viewport is to press the C key. This keyboard shortcut makes the active viewport into a camera view. If several cameras exist in a scene, then the Select Camera dialog box appears, from which you can select a camera to use. Figure 28-1 shows two Target cameras pointing at a car. The two viewports on the right are the views from these cameras.


Figure 28-1: A car as seen by two different cameras

You can turn off the camera object icons using the Display panel. In the Display panel, under the Hide by Category rollout, select the Cameras option. When selected, the camera icons are not visible in the viewports.

Cameras are usually positioned at some distance away from the rest of the scene. Their dis- tant position can make scene objects appear very small when the Zoom Extents button is used. If the visibility of the camera icons is turned off, Zoom Extents does not include them in the zoom. You can also enable the Ignore Extents option in the camera’s Object Properties dialog box.

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