# KBF00002 - Depth Blur Tool
Instructor : Pradeep Mamgain
This tool is used to create focal length effect or blurred depth effect. This tool only works when image contains Z-buffer channel. If image does not contain Z-buffer channel, you can remap Z-buffer channel using the luminance of channel of that image. You can also render a Luminance Depth Pass in 3D application and map its luminance to the aux channel.
# Tool Image
# Depth Blur Tool
First thing we have is Filter. Super Soften is high quality depth base softening effect. Soften is general softening filter while Box applies a Depth base box effect. Blur channel determines which channel is used to apply blur effect. We have regular RGBA channels and an additional Luma channel. By default Lock X/Y check box is always on, it allows you to symmetrically blur the image in X and Y direction. Blur Size is the strength of blur applied to the input image. Focal point is only visible when Blur Channel is set to Z. Decreasing this slider will move focal point closer to the camera. You can either set the focal point manually by dragging the slider or if you drag the pick button and hover mouse over the view displaying the image having Z-buffer info built in, without releasing the mouse button, fusion can set focal point for you interactively.Depth Of Field controls the depth of the area in focus. Have a look at the image displayed left. Focal point is set to 283 and DOF is 403. Any pixel that falls between the Z-depth 283 and 403 would remain in focus. Z Scale is used to expand the Z channel. It scales Z channel by the slider value. Below is the output of the image when depth blur setting shown in the image left applied. You can notice that region away from camera is blurred.
Open the fusion comp depthblur.comp. Add a depth blur node at the end of cubes.mov so that cubes.mov's output is connected to the DepthBlur1 input node. Display it in one of the display views. Also import Luminance Depth Pass using loader tool. Now drop a channel boolean tool and connect Luminance Depth output node to channel boolean's background. In channel boolean's Channel tab set Operation to Copy and Set To RGBA to Do Nothing as shown in the image below. Click on the Aux Channels tab and turn on Enable Extra Channels and change to Z buffer to Luminance FG.
Once you map Luminance FG to Z-buffer and display channel boolean node in one of the display view. Press Z key to see the Z buffer pixels, you would notice that now our image has got the Z depth. Now connect output node of the channel boolean to Green blur image node of depth blur tool. Play with the depth blur node's options and you would get decent depth blur effect. Your flow tiles should look like image below.
#Other Info
# eyeon Fusion KB # Adobe After Effects KB # Autodesk Maya KB # Composting Passes Inside Fusion