Z-depth

The Z-Depth Render Element is a grayscale image that renders each pixel based on its distance from the camera in the view.

Overview

The Z-Depth Render Element provides information about each object's distance from the camera in the current view. Each pixel representing the object is evaluated for distance individually; different pixels for the same object can have different grayscale values. In this render element, objects (or portions of objects) closest to the camera appear as black, while those furthest away appear white. Objects between the furthest and nearest points are rendered in varying shades of gray. The darker the gray, the closer an object pixel is to the camera.

The most common usage of the Z-Depth Render Element is as a control for depth of field in the composite. Depth of field can be challenging to do correctly within Maya, requiring many tweaks and re-renders; using the Z-Depth Render Element in a composite is usually much faster, and allows easier and faster adjustment than trying to get it exactly right within the render from Maya.

UI Path: ||Display Render Settings button|| > Render Elements tab > Z-depth

Attributes

The parameters for this render element appear in the Attribute Editor under Extra V-Ray Attributes.

Enabled – When checked, the Z-Depth pass appears in the V-Ray Frame Buffer.

Deep Output – Specifies whether to include this render element in deep images.

Use Depth From The Camera – Specifies whether to use the camera clip boundaries as the minimum and maximum Z-Depth distance. Enabling this option disables the Depth Black and Depth White parameters.

Depth Black – Objects up to this distance from the camera render as black. This option is available only when Use Depth From The Camera is disabled.

Depth White – Objects further than this distance from the camera render as white. This option is available only when Use Depth From The Camera is disabled.

Depth Clamp – Clamps the Z-Depth colors to a linear 0-1 range.

Filename Suffix – The text added to the end of the rendered file, when saved as a separate file (e.g. myrender.zDepth.vrimg).

Filtering – Applies the image filter to this channel. Image filter settings are in the Image Sampler rollout in the VRay tab of the Render Settings.

Don't Filter Environment – When enabled, only outlines of overlaying objects are filtered. When Filtering is enabled and Don't Filter Environment is enabled, pixels bordering scene objects and the environment remain unfiltered, while pixels bordering different objects are still filtered.

Force Black At Infinity - When enabled, overrides the infinity color, turning it black. Everything beyond the Depth White amount (if not using Depth From The Camera) is the infinity color.

Depth Black and Depth White

The Z-Depth Render Element parameters for minimum and maximum depth, Depth Black and Depth White, can be set to various values to provide different ranges of depth in the render element. In these examples, clamp zdepth is enabled.

Black = 368, White = 31900

Black = 1552, White = 31900

Black = 0, White = 17740

Black = 0, White = 4090

Use depth from the camera has been turned on

Common Uses

The Z-Depth Render Element is useful for adding depth of field to the final image in post production using a compositing application without the need for re-rendering. It can also be used to create basic fog by overlaying it on the composite with Add mode or Screen mode, with color correction as needed.

ZDepth Render Element

Original Beauty Composite

Depth of field applied to composite
using Z-Depth Render Element

Notes

• The Z-Depth Render Element will always be written as a 32-bit channel for multichannel .exr files. Even when outputting a 16-bit multichannel .exr, the Z-Depth channel will be 32-bit while the other channels will be 16-bit.