What is Z Depth?
Today, I will explain to you guys what is Z Depth. Because many of you will undoubtedly not be familiar with z-maps, their creation, or their use.
The term z-map might be a little misleading to those who are not familiar to working in 3D space. In high school geometry class the concept of two-dimensional space: the x-axis represents horizontal space and the y-axis represents vertical space. Whenever you work in packages such as Painter, Photoshop, Commotion, Combustion or After Effects you are working solely in 2-dimensional space. When you work in 3D you have, in addition to the x- and y-axes, a z-axis, representing depth.
A z-map is a grayscale image, similar to an alpha channel that is a graphical representation of depth. An alpha channel uses 256 levels of gray to determine masking, transparency, etc. - in a z-map every pixel in a scene is assigned a 0-255 grayscale value based upon its distance from the camera. Traditionally the objects closest to the camera are white and the objects furthest from the camera are black.
The following figure shows you the main scene with z-map.
The most common use is to use it as a control layer for a blur operation, 3D matte extract, Fog 3D, depth of field (simulating what a real camera would see), depth matte, Id matte and various others.
Depth of Field in Action:
Depth Matte in Action
Fog 3D in Action
I achieve these effects in Aftereffects.
In the end, there are two main ways to create a z-map with a 3D application or by faking it in 2D. If the depth effect you are going to apply is intended for a rendered 3D element you're better off making one in the 3D application itself, it's the most accurate way. For a 2D scene you can either fake one with gradients or replicate the scene precisely in a 3D application and create it there - it goes without saying that the gradient method is the easier of the two. But both ways in 2d are very time-taking and if the camera is moving then think of a God.
I hope you guys like and learn from this tutorial and if really learn something and any question, comments then please email.
Bye for now