Working with a null object

A null object is an invisible layer that has all the properties of a visible layer, so that it can be a parent to any layer in the composition. You’ll use a null object to scale the layers of the 3D object down to a more manageable size. If you began to scale each of the individual layers, you’d have to reposition each of them again. This way, you can parent all the layers to a single null layer, and then as you scale the null layer, all the other layers follow, maintaining their relationship to each other.

1 With the Timeline panel active, choose Layer > New > Null Object. After Effects names the layer Null 1.

2 Select the 3D Layer switch () for the Null 1 layer to make it three-dimensional. The null object moves to the origin point of the composition, at the center of the grid. Though you can see the null object in the Composition panel, remember that there isn’t really anything there—it’s an invisible layer. The representation of the object is to help you keep track of it as you work with it.

3 In the Timeline panel, select the Pages layer, and then Shift-click the AEFront.jpg layer to select all the layers in between. (Only the 3D Grid and Null 1 layers should not be selected.)

4 Select 1. Null 1 from the Parent pop-up menu for the Pages layer. The same selection is automatically applied to all selected layers.

Because the 3D object layers are now parented to the Null 1 layer, any changes to the null object also affect them.

5 Select the Null 1 layer in the Timeline panel, and press S to reveal its Scale property. Then change the Scale amount to 20, 20, 20%.

_ Note: Because the are linked, you need only enter the value once to affect all three axes.

The entire book is smaller, and each of the elements retains its relationship with the others.

6 Select the Track Z Camera tool (), hidden behind the Orbit Camera tool () in the Tools panel. Then drag to the right in the left view of the Composition panel to zoom in so you can see the book more clearly.

7 Select the right view in the Composition panel to make it active. Then choose Active Camera from the 3D View pop-up menu at the bottom of the Composition panel.

8 Choose File > Save to save your work so far.

Дата добавления: 2014-11-20