Distance Mask

In work

This mode results in a grayscale image, with objects represented in shades of gray based upon their distance from the camera. Nearby objects are black, distant objects are white, and objects inbetween are progressive shades of gray. You can use the Distance Mask image to produce depth-of-field effects using a 2D graphics application.

This mode can be used to create several distance effects. Refer to "Adding Depth" for more on using Distance Mask images.

Distance Mask Render mode produces an image that can be used as a distance mask in most image-editing applications. The Distance Render image contains grayscale representations of all the images in your scene. Objects closer to the camera appear black, while those furthest away appear white. The objects in between are various shades of gray depending on their distance from the camera.

This grayscale information can be used to create photographic depth of field effects. For example, if you take an image that has a lighthouse in the foreground and a fishing village in the background and render it using Distance Mask Render mode, you can take the image into Photoshop and create an image where the lighthouse is in sharp focus while the village is blurred.

Do this by rendering the image as distance mask, using Distance Mask Render mode, and then using an image editing application to place the distance mask into the original image's alpha channel. Once the Distance Render is in the alpha channel, you can apply filters to create photographic depth of field.

To render a scene as a distance mask:

1. Click the triangle next to the Render controls and choose Distance Mask from the menu.
   
   
2. Choose File > Export and choose PICT.
3. Choose the drive and folder where you want to save the file.

Using Photoshop

The following procedure uses Photoshop as a post production application. The steps for Corel Painter would be almost the same.

To create depth of field using Photoshop:

1. Render the scene normally using Perspective Render mode.
2. Save the image in a convenient location.
3. Render the scene again, this time using Distance Mask Render mode.
4. Save the mask image to the same location.
5. Open the Perspective Render and the Distance Render images in Photoshop.
6. Place the Distance Render image into the alpha channel of the Perspective image.
7. Load the alpha channel as a selection.
8. Apply Gaussian Blur.

• Objects close to you will appear sharp while objects farther away will become progressively more out of focus.
• You can also invert the selection and apply Motion Blur to the image. In this case, objects in the foreground would be motion blurred, and the background would be sharp, as if you took a picture from a moving car.
• You could determine very specifically which objects in your scene are in focus and which are not. Select the Distance Rendered alpha channel and remap the gray values in the Curves dialog in Photoshop. Remap black input to lighter output, and the gray value of the desired focal object to black.

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