Add Visibility Track

The visibility track controls when you can see an object. Visibility tracks can be added only to objects.

• Track View > In the Controller window, highlight the track of the object whose visibility you want to animate. > Edit menu > Visibility Track > Add
• Track View > In the Controller window, highlight the track of the object whose visibility you want to animate. > Tools Toolbar > (Add Visibility Track)

You can create a visibility track by either animating the Visibility parameter on the Object Properties dialog or by selecting an object in the Track View Hierarchy and clicking Edit menu Visibility Track Add. Doing either creates a visibility track, using a Bezier float controller, in Track View. The visibility track displays as a child of the object in the Track View Hierarchy.

Note: To animate an object's visibility with the Object Properties dialog Visibility parameter, Rendering Control must be set to By Object on the dialog.

Warning: An object without mapping coordinates that is invisible at frame 0 will not ask for UVW Map coordinates at render time. The warning will display at the frame that the object becomes visible. This can stop a render midway, so make sure objects that are invisible at the beginning of your animation have mapping coordinates if necessary.

On and Off Visibility

When you first assign a visibility track to an object, a Bezier float controller is automatically assigned; this allows visibility to change over the course of the animation. You can make an object appear or disappear suddenly by changing the interpolation of the visibility keys to Step tangency or with the On/Off controller.

Variable opacity is supported in the shaded viewports. For ease of use, the object never completely disappears from the viewports.

Visibility Inheritance

An object can inherit the visibility of its parent (as determined by the parent's Visibility track in the Track View). Use the Object Properties Inherit Visibility checkbox to specify the visibility inheritance of an object.

Groups and Visibility

All members of a Group inherit the visibility of the parent when a visibility controller is assigned to the parent. Transparent materials and hidden objects have no effect on this function.

Level of Detail Utility and Visibility

The Level of Detail utility lets you construct an object that alters its geometric complexity or level of detail based on its size in the rendered image. You create several versions of the same object each with different levels of detail; you group them as one, and then assign the Level of Detail utility. This automatically creates a special LOD controller as a Visibility track.

Procedures

To add a visibility track to objects:

1. In Track View, highlight the object you want to affect in the Hierarchy list on the controller window.
2. From the Track View Edit menu, choose Visibility Track Add.

A visibility track appears below the selected object(s). Add and edit keys in the visibility track to control the object's visibility.

To add visibility keys:

1. Once you have a visibility track assigned to the object, highlight the track.
2. On the toolbar, click (Add Keys).
3. On the Track View Key window, click in a visibility track to add a key at that time location.

Example: To create and animate a visibility track using the Object Properties dialog:

1. Create a box.
2. Turn on (Auto Key).
3. Drag the time slider to frame 10.

   This is the frame at which you'll set the box to disappear.

4. Right-click the box and choose Properties from the shortcut menu.
5. In the General tab, set Visibility to 0, and then click OK.

   This creates a visibility track in Track View and adds a key with a value of 0 to the track.

6. Scrub the time slider.

   The box fades.