Basics: Compositing 101

We start a new chapter of our Basics series, exploring how to make the most of an artist’s animations and images via compositing

We explore the fundamentals

In our Basics series, we look at the fundamentals of a wide range of different topics in CGI to break it down into the core elements. This month we delve into compositing.

Why does an artist need compositing? Surely everything can now be done in a render? The latest generation of render software can now create imagery on a laptop in minutes, which five years ago would have taken hours on a workstation costing the same price as a nice car.

The answer to why we need compositing is straightforward. Compositing allows a level of refinement of the imagery or animation that is still hard to achieve in 3D software. A decent compositing application also possesses an NLE (non-linear editor) which allows shots to be stitched together, retimed, colour matched and reordered according to the needs of an artist, as well as the client.

A well-managed composite can change a colour in a sequence of shots or pop out a specific reflective highlight in less time than any 3D software could manage. Compositing software also offers a wide range of effects, enabling you to add particles, glows and text in a quicker and more adaptable way than with 3D software. Some compositing software can also take the raw building blocks of a 3D scene and import it as a 3D file via formats such as Alembic, which can be used to create new elements and masks for existing footage.

Finally, compositing software enables an artist to take the best elements of any 3D software, such as a character from Maya, a simulation from Houdini, and a motion graphics scene from Cinema 4D, and combine them into a single shot. Compositing allows the shot to look better than it ever would have if it had been created in just a single piece of software.

For this series of compositing basics, we will be using the free version of Blackmagic Design’s Davinci Resolve software, which offers all of the key features mentioned above.

01 STARTING WITH DAVINCI RESOLVE

When first launched, Davinci Resolve presents a helper window to set up an untitled project for the first time. A Davinci Resolve project contains all of the timelines and Fusion Compositions. A project does not include the footage, which can live wherever the artists desire. Davinci Resolve stores projects as part of its directory structure away from a distinct location, such as a Documents folder. To access the Project window and create and manage projects after the initial launch, you can select the small house icon at the bottom right of the screen.

02 MAKE A COMPOSITION

As this is the first introduction to compositing, let’s find out where the compositing workflow lives within Davinci Resolve. The software has seven different 'Pages' each dedicated to a different workflow. In the Media page, which is accessed either by the leftmost icon at the bottom of the Davinci Resolve screen or via the Workspace>pages> Media menu, create a new Fusion Composition by rightclicking in the Media Pool window at bottom. Choose New Fusion Composition and give it a name.

03 WORK WITH NODES

Double-click on the new Fusion Composition and this will open the Fusion page and show the contents. Fusion is a nodal compositor, which means each element that is used to create the finished shot, whether it is footage, an effect or even a basic transform, is represented as a 'Node' via an icon in the Nodes window. Nodes are connected via pipes that flow in a single direction, starting with footage or a generated image element, and flowing to the Mediaout node, which shows the final result.

04 CREATE A NODE TREE

Fusion has a wide array of nodes to choose from, which can either generate imagery or work with existing footage via a Mediain node. The most common nodes are available in a strip in the middle of the Fusion page. These can be dragged into the Node viewer. Select a Background node, which is the leftmost icon, and pull that into the Node window. The Inspector for the elected Background node allows parameters such as colour to be changed. Click and drag from the small square on the right of the Background node and connect it to the Mediaout node. This is a successful node tree. •