The Scene View control bar lets you choose various options for viewing the scene and also control whether lighting and audio are enabled. These controls only affect the scene view during development and have no effect on the built game.
The first drop-down menu selects which Draw Mode will be used to depict the scene. The available options are:
These modes let you view each of the elements of the G-buffer (Albedo, Specular, Smoothness and Normal) in isolation. See the page on Deferred Shading for further details.
The following modes are available to help visualise aspects of the Global Illumination system: UV Charts, Systems, Albedo, Emissive, Irradiance, Directionality and Baked. These modes are described with examples on the GI Visualisations page.
To the right of the render mode menu are three buttons that switch certain scene view options on or off:
The menu (activated by the small mountain icon to the right of the Audio button) has options to enable or disable rendering effects in the scene view.
The Effects button itself acts as a switch that enables or disables all the effects at once.
Gizmos are graphics added to the scene (either by Unity itself or from your own scripts) that help with visualisation and identification of items in the game world. For example, you can add icons to help identify your game objects and use simple wireframe graphics to show otherwise invisible paths and positioning elements. See the Script Reference page for the OnDrawGizmos function for further information about implementing custom gizmos in your scripts.
Clicking the Gizmos popup will show a menu with a number of options:
The 3D Gizmos checkbox determines whether gizmos are shown in true 3D (with correct obscuration and perspective) or as a simple overlay on top of other scene graphics. The slider to its right adjusts the scale of gizmo icons relative to other objects. The Show Grid checkbox below switches the standard scene measurement grid on and off.
Beneath these options is a table of component names with Icon and Gizmo columns to the right. The list is subdivided into user scripts and built-in components and will also maintain a section of recently changed items as you make modifications.
The Icon column lets you select the gizmo icon displayed for particular component types. For built-in components, the only options are to have no icon (as with Colliders, where only a wireframe gizmo is shown) or simply to switch the standard icon on and off (as with Cameras, Lights and Audio Sources, among others). For user scripts, clicking the icon column will bring up a menu to select the desired icon:
This lets you select from a variety of simple standard icon shapes in different colors that you can use to identify particular script types. The Other button will bring up a texture selector from which you can choose any texture you like to use as the icon for your script.
The Gizmo column in the table contains a checkbox that lets you choose whether gizmo graphics will be drawn for a particular Component type. For example, Colliders have a predefined wireframe gizmo to show their shape while user scripts can draw custom gizmos appropriate to their purpose; these gizmos can be turned on or off by clicking in this column.
The rightmost item on the control bar is a search box that lets you filter items in the scene view by their names and/or types (you can select which with the small menu at the left of the search box). The set of items that match the search filter will also be shown in the Hierarchy view which, by default, is located to the left of the Scene view.