Using Layers

So what does 3ds Max have in common with a wedding cake? The answer is layers. Layers provide a way to separate scene objects into easy-to-select and easy-to-work-with groupings. These individual layers have properties that can then be turned on and off.

CROSS-REF 

Animation sequences also can be split into layers using the Animation Layers. You can learn more about these layers in Chapter 30, "Using Animation Layers."

Using the Layer Manager

You create, access, and manage layers through the Layer Manager dialog box, shown in Figure 7.17. This dialog box is a floater that can remain open as you work with objects in the viewports. You can access the Layer Manager using the Tools Layer Manager menu command, by clicking the Layer Manager button on the main toolbar, or by clicking on the same button in the Layers toolbar.

Figure 7.17: The Layer Manager lists all the layers and the objects contained within each layer.

After you've set up your layers, you can control them using the Layers toolbar, shown in Figure 7.18, rather than having the Layer Manager open. You can access the Layers toolbar by right-clicking the main toolbar away from the buttons and selecting the Layers toolbar from the pop-up menu or by selecting the Customize Show UI Floating Toolbars menu command.

Figure 7.18: Use the Layers toolbar to set the active layer.

Table 7.4 lists the buttons found in the Layer Manager.

Table 7.4: Layer Manager Buttons
Open table as spreadsheet

Button Icon	Name	Description
	Create New Layer	Creates a new layer that includes the selected objects.
	Delete Highlighted Empty Layers	Deletes a layer if the layer is highlighted and empty.
	Add Selected Objects to Highlighted Layer	Adds any selected objects to the current highlighted layer.
	Select Highlighted Objects and Layers	Selects in the viewports any highlighted layers or objects.
	Highlight Selected Object's Layers	Highlights the layer of the viewport's selected object in the Layer Manager.
	Hide/Unhide All Layers	Toggles between hiding and unhiding all layers.
	Freeze/Unfreeze All Layers	Toggles between freezing and unfreezing all layers.

With the Layer Manager open, you can create new layers by clicking the Create New Layer button. This adds a new layer to the manager, names it "Layer01," and includes any selected objects as part of the layer. If you click the layer's name, you can rename it. Layer 0 is the default layer to which all objects are added, if other layers don't exist. Layer 0 cannot be renamed.

Note 

Although you can rename layers in the Layer Manager, you cannot use the Layer Manager to rename objects. To rename an object from the Layer Manager, simply click on the object's icon to open the Object Properties dialog box where you can change the object's name.

Creating a new layer automatically makes the new layer the current layer as denoted by the check mark in the first column of the Layer Manager. All new objects that are created are automatically added to the current layer. Only one layer can be current at a time, but several layers or objects can be highlighted. To highlight a layer, click it in the Layer Manager. Highlighted layers are highlighted in yellow.

A highlighted layer can be deleted with the Delete Highlighted Empty Layer button, but only if it is not the current layer and it doesn't contain any objects.

Newly created objects are added to the current layer (the one marked with a check mark in the first column of the Layer Manager). If you forget to select the correct layer for the new objects, you can select the objects in the viewports, highlight the correct layer, and use the Add Selected Objects to Highlighted Layer button to add the objects to the correct layer.

Note 

Every object can be added only to a single layer. You cannot add the same object to multiple layers.

The Select Highlighted Objects and Layers button selects the highlighted layers (and objects) in the viewports. This provides a way to select all the objects on a given layer. If an object in the viewports is selected, you can quickly see which layer it belongs to with the Highlight Selected Object's Layers button.

If you expand the layer name in the Layer Manager, you see a list of all the objects contained within the layer. If you click the Layer icon (to the left of the layer's name), the Layer Properties dialog box, shown in Figure 7.19, opens. Clicking the Object icon opens the Object Properties dialog box.

Figure 7.19: The Layer Properties dialog box is similar to the Object Properties dialog box, but it applies to the entire layer.

Using the Layer List

The main section of the Layer Manager (and repeated in the Layers toolbar) is the layer list and its columns, which allow you to turn certain properties on and off. The properties in the columns include Hide, Freeze, Render, Color, and Radiosity. If a property is enabled, a simple icon is displayed; if disabled, a dash is displayed. If an object is set to get its property from the layer (by clicking the ByLayer button in the Object Properties dialog box), then a dot icon is displayed. Individual objects within a layer can have different properties. You can sort the column properties by clicking on the column head.

You can toggle these properties on and off by clicking on them. You can also set these properties in the Layers toolbar. The Hide toggle determines whether the layer's objects are visible in the viewports. The Freeze toggle makes objects on a layer unselectable. The Render toggle enables the layer's objects to be rendered. The Color toggle sets the layer color. Layer 0 is set to assign random colors and cannot be changed. The Radiosity toggle includes the layer's objects in the radiosity calculations.

The Layer Manager also includes a right-click pop-up menu that includes many of the same commands found as buttons, but a unique set of commands found in the right-click pop-up menu are the Cut and Paste commands. With these commands, you can select objects in one layer to cut and paste into another layer.

Caution 

If multiple objects are selected within the Layer Manager, then right-clicking on an object's name deselects all the selected objects. To maintain the current selection, right-click within the Layer Manager, away from the Layers column.

Tutorial: Dividing a scene into layers

As a scene begins to come together, you'll start to find that it is difficult to keep track of all the different pieces. This is where the layers interface can really help. In this example, we take a simple scene and divide it into several layers.

To divide a scene into layers, follow these steps:

1. Open the  Elk on hill layers.max scene file.

   You can find it in the Chap 07 directory on the DVD. This file includes an Elk model created by Viewpoint Datalabs.

2. Select Tools Layer Manager to open the Layer Manager.

3. With no objects selected, click the Create New Layer button and name the layer Hill and trees. Click the Create New Layer button again, and name this layer Elk. Click the Create New Layer button again, and create a layer named Background and light. The Layer Manager now includes four layers, including layer 0.

4. In the Layer Manager, click on the first column for the Elk layer to make it the current layer. With the Edit Select All (Ctrl+A) menu command, select all objects in the scene and click the Add Selected Objects to Highlighted Layer button in the Layer Manager.

5. Expand the Elk layer by clicking the + icon to the left of its name. This displays all the objects within this layer.

6. Select all the trees and the hill objects by holding down the Ctrl key and clicking each object's name in the Layer Manager. Then right-click away from the names, and select Cut from the popup menu. Then select the Hill and trees layer, and select Paste from the right-click pop-up menu.

7. Select the background and light objects from within the Elk layer, and click the Select Highlighted Objects and Layers button. Then select the Background and light layer, and click the Add Selected Objects to Highlighted Layer button to move the background and light objects to the correct layer.

You can now switch between the layers, depending on which one you want to add objects to or work on, and you can change properties as needed. For example, to focus on the deer object, you can quickly hide the other layers using the Layer Manager. Figure 7.20 shows the various layers and the objects in each layer.

Figure 7.20: All objects assigned to a layer can be viewed in the Layer Properties dialog box.