Nuke General Compositing Techniques

Introduction
Film compositing veteran Jonathan McFall offers this workshop on Nuke compositing techniques. This lesson presents a myriad of techniques to manipulate and then integrate 2D elements into a photorealistic 3D panoramic matte scene. Jonathan revels the quick way AND the professional way to achieve cinematic results.

Finding And Prepping The Elements
First we prepare the photos from the internet for the matte painting by quickly keying the photos to create nice alphas. Some parts will require a bit of roto to create garbage mattes. Next, we start building the silhouette of a factory from random images and light the scene from random night-time photos. Clean up the script to make the computer run a little faster and render out an image sequence in Nuke with an aplha.

2D In A 3D Environment
We begin to recreate the 2D scene in Nuke's 3d environment by projecting each on to cards so that you get exactly the same out put, but now in the 3d environment. Simply move the cameras and cards to scale the photos, rather than using the 2d transform node. To add realism and marry the various elements together we will now: make the clouds animate, use the zblur, use the focal plane setup, use the depth of field and lastly create a custom bokeh from scratch with the convolve tool.

The Fine Details
In this chapter we dive down to the adjust the finest details to achieve realism. A de-spill expression on blue and green screens offers production quality. DE-noise and then RE-grain in two different ways: the quick way and the professional way. Channel by channel, plate by plate this workflow matches the grain between each element in the scene. We wrap up the chapter with a fun bit of chromatic aberration (chromatic distortion) with two different methods.

Distress For A Miracle
All of chapter 5 is to recreate the imperfections that a camera creates in real life. To simulate reality is to make a better and more realistic matte painting. Its not just about making everything look as clean as possible, sometimes you have to make it look dirty too. Lets add some fire frames and retime the footage. Extend the project settings to a panoramic ratio. Included is a detailed explanation of the shuffle / shuffle copy nodes. Zdepth with color grading is employed for very subtle addition of realism. Next, we use a colourful bokeh to blend the foreground in and to simulate smudges and dust on the camera lens. Further use of defocus and chromatic aberration creates the illusion of a real camera viewing a real landscape. Jonathan offers many small adjustments and variations in this final chapter attempting to achieve the 'miracle' when photorealism occurs.