Objects like brushes and entities can be placed on layers which are basically a mechanism to group objects logically. Each layer can be stored as a separate .lyr file on the harddisk. Having the layer files stored separately on disk allows to do collaborative editing, since the layer files can be checked in individually in a revision control system like Perforce.
You can find the Layer Tab on the RollupBar. On the Layer's tab are a few useful buttons and the layer list. By default, the level's objects will be located on the "main" layer.
Note in the screenshot that several layers have an asterisk after them. This shows layers that have had changes made to them.
Creating a New Layer
To create a new layer, click the New Layer button. After clicking on it, a dialog box will be displayed:
Be sure to enter a useful and recognizable name for your layer, possibly indicating its function or a description of what it contains. For example "beach area" or "sounds". In the dialog box you can also specify if the Layer is visible by default, is external, will be exported to the game, or should be frozen by default.
Deleting a Layer
Click the Delete Layer button to delete the currently selected layer. A dialog box will show up and ask for confirmation. Once a layer is deleted, it cannot be restored without reloading a previous version of the level, or re-importing the layer if it was external.
Renaming a Layer
Click the Rename Layer button which opens a dialog box that allows you to rename the currently selected layer.
Exporting a Layer
Click the Export Layer button to open a Save As dialog, allowing you to export your layer to a file. Make sure your layer file has the .lyr extension to it. This layer file can be imported into other levels, if required.
Importing a Layer
Click the Import Layer button to import a layer that was exported previously. Locate your layer using the Open File dialog.
Assigning Objects to Layers
When you have more than one layer in your level, you can assign a specific layer to each of your objects. Select an object and look at its Entity settings on the RollupBar. Click the Layer button to select a different layer. The image below shows a SpawnPoint entity selected, and the Layer's button selected on the RollupBar.
By default any object is placed in the layer "Main", unless you have selected another from the layers menu. If a different layer is selected from the Layer's tab, any objects added to the level will automatically be assigned to that layer.
Hide/Show and Freeze/Unfreeze Layers
After assigning layers to your objects, there are a few additional ways to manage them. Go to the layer list in the RollupBar.
Toggling the eye icon will hide/show the objects on that layer.
Toggling the arrow icon will allow interaction with objects when the icon is visible (objects are unfrozen), and disallow interaction when the icon is hidden (objects are frozen).
Double clicking on an icon will make all layers change their state of hide/show or frozen/unfrozen, depending on which icon was selected.
To change layer settings, right click on a layer and select Settings in the popup menu. The same dialog box as for creating a new layer will be displayed. Change the settings and click OK.
Does the same thing as the layer hide/show icon.
Does the same thing as the layer freeze/unfreeze icon.
When this checkbox is enabled, the layer will be stored as a separate .lyr file on disk, enabling better use of version control systems. The layer will automatically be exported when your level is saved, and imported on loading. Unchecking this box will make the layer part of the .cry file again and the external .lyr file will no longer be updated. External layers are indicated by an underlined layer name.
Export to Game
When this checkbox is enabled, the layer will be exported to the game when you use File->Export to engine. Uncheck this if you don't wish to see the objects contained in the layer in pure game mode.
Layer Activation and Deactivation
It is possible to activate and deactivate all entities in a specific layer by using the Engine:LayerSwitch flownode. Also brushes and solids can be hidden/unhidden using this node.
Just type in the correct layer name and trigger the inputs.
Layer Switching needs to be globally enabled in the level in order to work.
In the Rollup Bar, switch to the "Terrain" tab, then select "Environment" and set "UseLayersActivation" to true (which is in the "EnvState" section).
Entities which are set to Hidden In Game will not unhide if the Unhide input is triggered.
Picked up objects will disappear in the player's hands when their layer gets hidden.
Only entities, brushes and solids are affected.
A layer which gets hidden/unhidden should never contain AI to avoid conflicts with Territories and Waves.
The layer switch has nothing to do with streaming.
The Layer input on the Flow Graph node is case sensitive.