Depth compositing with image planes

Maya’s image plane features real-time z-depth compositing in the camera scene view. This z-depth compositing feature allows you to place 3D objects further and closer within the field of view of the camera together with an image plane mapped with depth information. Objects that are closer than depth values in the image will appear in front of it. Objects that are further than depth values in the image will appear behind it.

The z-depth data is contained within the z channel of an .iff image file mapped to the image plane.

The z-depth data is used to offset the image plane’s pixels relative to its camera. Therefore, the z-depth feature only works for the image plane’s respective parent camera. Other cameras will not be able to visualize image plane depth.

By default, z-depth map support is disabled, even if the image file contains z-depth values. To enable Z-depth support, follow these steps.

To enable depth map support of your image plane

1. Select View > Select Camera to select the current camera.
2. In the Camera’s shape node, expand the Environment section in the Attribute Editor. Click the Create button to create an image plane.
3. In the image plane Attribute Editor, expand the Depth section.
4. Check the Use Depth Map option to enable z-depth support.

   If z-depth data exists in the specified image file, then it is represented in the scene view; or, the software render has composited z-depth information.

To optimize performance, it is recommended that image resolution be an integral multiplier of the render output resolution (for example, set the image resolution at two times the render output resolution and not two and a half times). Otherwise, the image may need to be resampled to fit in the render area.

Note:

• Currently, you can only use z-depth compositing with .iff image files.
• Z-depth compositing is not supported by the mental ray for Maya renderer.
• A camera that has more than one image plane with z-depth data may not render properly in the scene view. However, a camera that has only one image plane with z-depth data will render properly in the scene view even if that camera also contains multiple image planes with no z-depth data. Software rendering is not affected in either case.
• Partially transparent pixels may not render correctly because depth information is usually undefined at their color value.
• When z-depth compositing is enabled, the image plane cannot be rotated.
• Occasionally, when z-depth data is resampled for display in the scene view, you can see rendering artifacts where depth values do not line up with the color information. Software rendering is not affected.