Previewing Interactively with the Render Region

You can view a rendering of any section or object in your scene quickly and easily using a render region. Rather than setting up and launching a preview, you can simply draw a render region over any 3D view and see how your scene will appear in the final render. Each view can have its own render region with its own settings.

Because the render region can use the same renderer as the final render, you can set the region to render your previews at final output quality. This gives you a very accurate preview of what your final rendered scene will look like.

You can resize and move a render region, select objects and elements within the region, as well as modify its properties to optimize your preview. Whatever is displayed inside that region is continuously updated as you make changes to the rendering properties of the objects. Only this area is refreshed when changing object, camera, and light properties, when adjusting rendering options, or when applying textures and shaders.

When the render region is refreshed, a series of tiles starts filling in the region with the rendered image. Each time you change properties that affect the appearance of objects in your scene, the region is automatically refreshed. You do not have to wait for the region to finish refreshing to make more changes to your scene — a change simply interrupts the current refresh and restarts it to include the updates you have just made. This allows you to do iterative adjustments on the properties.

Click for more Options (A), Store and Compare (B), and Hide the Region (C).

Creating a Render Region

You can draw a rectangular region of any size around the objects you want rendered interactively within any 3D view. You can draw only one render region at a time in any view, but each viewport or Object View window can have its own region.

To create a render region

Do one of the following:
- Choose Render Regions Region Tool from the Render toolbar to activate the render region mode.
  
  The mouse pointer shows a square with a sphere in it to indicate that you are in region mode. You can now define a region in any 3D view.
  
  or
- Press Q to activate the render region tool.
Drag the mouse pointer diagonally across the 3D view to create the render region. The region is drawn as a box with a yellow border and blue resizing handles.
As soon as you release the mouse button, the region is drawn and whatever is displayed in that region is rendered.

The render appears as a series of tiles that fill up the region. Each tile is outlined with an angled bracket at each corner, signifying which tiles are being updated at each refresh. When you make a change that affects the visual appearance of the scene, only the part of the scene shown in the render region is rendered.

If you wish to start over, simply draw a new region anywhere you like.
Deactivate the render region tool by pressing Esc.

Note

To toggle the render region display on or off, press Shift+Q.
To delete the current render region, press Q to activate the render region tool and click in the view.
To have the render region update during playback, Play All Frames (All on the playback panel) must be active. The render region does not update in Real-Time Playback mode (RT).

Comparing Render Regions

The render region has memo-regions that allow you to store, compare, and recall settings. They look similar to the viewports' memo-cams (although they are not saved with the scene).

A	The left side shows the stored region.
B	The right side shows the current settings.
C	Middle-click to store, and click to display. The currently displayed cache is highlighted in white. Right-click for other options.
D	Drag the swiper to show more or less of one image or the other.

ImportantBe careful when comparing render regions. You should do this when you are only tweaking material and rendering parameters, and not making other changes to the scene. If you revert to previous settings, either accidentally or on purpose, you will lose any modeling, animation, or other changes you have made in the meantime.

To store the current region

Middle-click on a memo-region box.

The pixels are cached and displayed on the left side of the region. As soon as you modify your settings, the changes appear on the right.

Only the pixels inside the region are cached. Other pixels will be drawn stippled black and white if you move or resize the region.

The memo-region box whose cached pixels are being displayed is highlighted white, and other boxes with cached pixels are orange.

To display a stored region and compare it with the current settings

Click on an orange memo-region box.

To display the current settings only

Click on the white memo-region box.

To revert the scene to stored settings

Right-click on an orange or white memo-cam box and choose Revert Scene to Here.

Setting the Render Region Display Mode

The render region's display mode defines what channels the region displays. For example, you can display the RGB channels, the alpha channel, and so on.

To set the render region display mode

Do one of the following:

To change all render regions, choose an item from the Render Regions Display menu on the Render toolbar.

or
To change a specific region, click the triangle at the upper left of the regions (or right-click on the region's border) and choose an item from the Display menu.
- Alpha-blended RGB displays the RGB channels overlayed on the scene using the alpha channel.
- RGB only displays the RGB channels.
- Alpha displays the alpha channel of the scene in the render region. This is useful if you want to quickly check the accuracy of a particularly complex alpha channel.
- Red shows only the red channel.
- Green shows only the green channel.
- Blue shows only the blue channel.

Displaying a Render Channel in the Render Region

You can display any of the built-in, preset, or custom render channels available for your scene in the render regions. For information about setting up render channels, see About Render Channels.

To display a render channel in the render region

Do one of the following:

To change all render regions, choose an item from the Render Regions Render Channel menu on the Render toolbar.

or
To change a specific region, click the triangle at the upper left of the regions (or right-click on the region's border) and choose an item from the Render Channel menu.

Tracking Objects with the Render Region

Rather than always adjusting your render region's size and location while you are working in a scene, you can set the render region to track an object, hierarchy, group of objects, or even a part of an object (cluster).

To set the render region to track an object

Select an element and draw a render region large enough to contain its movement over the frame range.
Do one of the following:
- To track in all render regions, choose Render Regions Track Selection on the Render toolbar.
  
  or
- To track in a specific region, click the triangle at the upper left of the regions (or right-click on the region's border) and choose Track Selection.

As the object moves, only the pixels in a box containing the selected element are rendered. Selecting another object causes the render region to track the new selection.

TipIf you are working on a small part of an object and you would like to track a specific area rather than the entire object, select a cluster or tagged points on the object and click Render

Regions

Track Selection. The render region focuses on and tracks only the selected portion of the object.

Rendering Selected Objects

Rather than rendering everything in the render region, you can render only the selected objects. To do this, activate Render Selection Only in the render region options. See Setting Render Region Options.

To set the render region to render only selected objects

Select the objects that you wish to render.
Click the triangle at the upper left of the regions (or right-click on the region's border) and choose Options. In the Render Region Options property editor, toggle Render Selection Only.

The render region now renders only the selected objects.

Moving and Resizing a Render Region

You can resize and reposition the region in the 3D view by dragging its border. The mouse pointer changes to indicate the type of action you can perform with the region. The placement and size of the render region are limited by the layout and size of the 3D views themselves.

To move a region

Position the pointer on the border of the render region's bounding box. The pointer changes to a four-way directional arrow.
Click and drag the pointer in any direction to reposition the region. Once positioned, release the mouse button and the region is refreshed.

To resize a region

Position the pointer over one of the blue squares on the corners or borders of the render region. The pointer changes to a directional arrow.
Click and drag the pointer to resize the region. Release the mouse button and the region is refreshed.

Hiding the Render Region

Planning to make several consecutive changes to your scene and you don't want render region refreshes to launch one after another? Try hiding the region:

To hide a render region

Do one of the following:
- Press Shift+Q with the mouse over the desired view. Pressing Shift+Q again redisplays the region as it was defined prior to hiding.
  
  or
- With the Render Reqion tool active, middle-click in the view; middle-click again to unhide the region.
  
  or
- Click the X at the upper left of the region.
  
  or
- Click the triangle at the upper left of the region (or right-click the render region's border) and choose Hide Region.

To hide or re-display all render regions

Choose Render Regions Hide/Unhide from the Render toolbar.

If any regions are displayed, they become hidden. If there are no regions displayed, they all become displayed.

Closing the Render Region

Once a render region has been defined, and the render region tool is still active, click anywhere on the screen to close the region. You do not have to wait until the region is finished rendering.

Dragging a new render region over an existing one closes the original region and renders the new one.

TipDeactivate the render region mode by pressing Esc.

Setting Render Region Options

A render region renders the scene in the same way as a final output render. As such, the rendering options you set for a render region give you an accurate preview of what your final rendered scene (current render pass or render channel) will look like.

The render region uses its own set of renderer options that affect only the render region and are not used for the final render. If necessary, you can use the various copy commands to match the region renderer settings with those of the final output renderer (and vise-versa). See Copying Render Options.

Previewing the changes you make to your scene in a render region is an interactive process. To speed up the "tune-preview-retune" cycle, use the region's rendering options to optimize the display.

To open the render region property editor

Do one of the following:
- To open a combined property editor and make settings that affect all render regions, choose Render Regions All Options from the Render toolbar.
  
  or
- To open the property editor for the last view you clicked in (highlighted in white) and make settings that affect only it, choose Render Regions Active Viewport Options from the Render toolbar.
  
  or
- To set the options for a specific region, click the triangle on its upper left or right-click its border and choose Options.
- In the explorer, set the scope to Application and expand the Views node. Click the icon for the Render Region Options node that appears under ViewA, B, C, or D.

To set the renderer options

In the render region options property editor, do one of the following:
- Select the Use Current Pass Options checkbox to use the renderer options exactly as defined for the current pass. The renderer options are not displayed in the property editor, they are simply used as-is.
  
  or
- Deselect the Use Current Pass Options checkbox to use the renderer options based on the Region Renderer setting. The renderer options are displayed in the region property editor and you can set them as needed.

For more information about the region options, see the Render Region Options Property Editor [Properties Reference].

To set the accuracy of the region

If you are using the mental ray renderer, you can quickly set the rendering accuracy (sampling level) with the slider on the right side of the region border.

Position the mouse pointer over the blue rectangle on the right side of the region border. The Max Sample slider appears.
Drag the slider down to decrease the maximum sampling level and increase the render speed in the region.

For more information about setting the sampling level, see Controlling Aliasing.

Refreshing the Render Region

By default, the render region refreshes automatically each time you modify the region or change scene properties. You can optimize region refresh when moving, resizing, or applying changes to your scene elements by choosing to manually refresh the region.

You should deactivate the automatic refresh of the region if you are making a number of changes that require intensive rendering calculations, like caustics and motion blur. You can refresh the render region after you have set these options and made your scene changes.

There are three possible settings:

Interactive: Render regions refresh automatically for any change in the scene that might affect the rendering.
Camera, Time, and Region State: Render regions refresh automatically only when you modify the camera, change frames, or change the render region settings.
Manual: Render regions never refresh automatically.You must always refresh manually.

To control automatic refreshing of render regions

Do one of the following:

To change a specific region, click the triangle at the upper left of the regions (or right-click on the region's border) and select an option from the Refresh Mode menu.
To change all render regions as well as the default for new scenes, choose an option from the Render Regions Refresh Mode menu on the Render toolbar. This value is also stored in your Rendering Preferences.

To refresh render regions manually

Do one of the following:

To refresh a specific region, click the triangle at the upper left of the regions (or right-click on the region's border) and choose Refresh. Alternatively, you can right-click in a render region while the Region Tool tool is active.
To refresh all render regions, choose Render Regions Refresh menu on the Render toolbar.

Saving the Render Region to File

If you want to capture the contents of the render region for later use, you can save the region as a still image. The region's contents is saved to disk exactly as you see it and according to the display mode setting. For example, if you selected RGB Only as the display mode there will be no alpha channel written to the file that gets output.

To save the render region

Draw a render region in a 3D view.
Set the display mode to specify what color channels get saved to file. See Setting the Render Region Display Mode.
Click the triangle at the upper left of the regions (or right-click on the region's border) and choose Save As.
Using the browser, select a directory, format and file name for your image.

NoteAlthough you can save the render region before it is completely rendered, only the completed portion will be saved.

Setting Render Region Preferences

The render region preferences are a subset of the rendering preferences. They allow you to se the region's Track Selection state, its Auto-Refresh state, and its display mode.

To set render region preferences

From the main menu, choose File Preferences to open the preferences window.
Select Rendering from the explorer pane to open the Rendering property editor in the right pane.
Set the Region Settings as needed. See Rendering Preferences.