Nuke - An Introduction for After Effects Users
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Nuke for AE users

Pete O'Connell Pete O'Connell
Montreal, Quebec Canada
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Article Focus: Nuke, the new compositing tool from The Foundry, is rapidly becoming a favorite in high-end film production. Its price also offers an easy entry for indie producers who want to create better work, faster and more powerfully. Film compositor Pete O'Connell offers this guided tour of Nuke for AE users, along with tips for leveraging your AE experience in the brave "Nuke" world of VFX creation.

Nuke was originally developed for in-house use by Digital Domain, the effects house for over 60 major films. They won Academy Awards for their work on “Titanic” and “What Dreams May Come,” as well as nominations for “Apollo 13,” “True Lies,” and “I, Robot.” One of their most recent projects is “The Curious Case of Benjamin Button.” Nuke was released commercially just after the Academy gave Nuke a Technical Achievement Award in 2002.

The most recent version is 5.1, and it runs on Mac OS X 10.5 (Leopard, 32-bit only), Windows XP SP2, XP64 and Linux CentOS 4.5 (32-bit and 64-bit).

I work in Montreal for the Toronto-based effects house Mr. X, one of the world’s leading Nuke houses, which is one of the reasons I was excited to start working there. This article is an introduction to Nuke for people coming into Nuke from After Effects, like I did.



I am going to try to do a few similar tasks in both AE and Nuke and along the way I'll be pointing out a few important differences. A common first step in AE is to import footage into the project window.

Import footage into After Effects

In Nuke, you drag and drop an image onto -- or create a read node in -- what's called the "node graph". A little thumbnail icon of the image I dragged in from the finder is created in pretty much the same way that you get a small preview in AE's project window.


Import footage into the Nuke node graph



In Nuke, to view any footage in its native format, I hit any number on the alpha numeric keypad between 1 and 9. This brings the selected node up in the viewer. Each number at the top of the alpha-numeric keypad can load a different node for viewing in Nuke.

The shot I am working on here is intended to be 2k (2048x1556). I can fit my footage to these dimensions by adding a Reformat node, which can be found in the transforms menu. Nuke's Reformat node does the same job in many ways as AE's Comp Settings dialog box.

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Nuke Reformat node



The Grade Node

In Nuke, to do a basic colour correction, I select a grade node from the colour correction menu (similar to AE's Levels Effect) and attach it to the reformat node. In the grade node's properties tab I'm going to move my gamma slider down and my multiply slider in order to increase the contrast of the image .In the image below we are viewing the Grade node properties panel, however we are not yet viewing the result of the node's colour correction because the node hasn't yet been connected to a viewer.

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Nuke Grade node not yet applied

The Reformat node is connected to input number 3 (which I connected by selecting that node and hitting the number 3). No other nodes are connected of the three possible nodes we have so far.

I'm now going to select my grade node by clicking once on it and then hitting the number 4 on the alpha-numeric keypad. So long as my mouse is hovering over the viewer and I hit "3" and "4" I'll be able to go back and forth visually between the two states.

Here we see the image with the Grade Node's color correction applied.

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Nuke Color Grade Node applied

In AE, I can do something similar by pulling down the 'Gamma' and pulling up the 'Upper White' of the Levels effect's properties. The results are much the same. In AE, however, If you are doing any kind of aggressive colour correction you will need to be working at a higher bit depth than just 8 bit.

For example. if I'm going to be doing a colour correction in AE where I set the "Output White" of one instance of the Levels effects way down to 10 (instead of its default of 255) and follow that with another instance of the Levels effect to brighten the image back up, my image will get posterised. This is not in itself a big deal cause we can always promote the project up to 16 bit to get a nice smooth image.

However some care must still be taken since certain AE effects (Cycore effects, for example) are still only 8 bit, so even-though a project might be 16 or 32 bit, 8 bit effects in the render order will sometimes demote a comp back down to 8 bit, which can cause banding in the darks and in the case of 32 bit projects, clipping of the highlights.


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Extreme color correction in AE shows banding

In Nuke this is never a problem. We can do a very aggressive colour correct and if we negate it by a subsequent colour correct, we'll get an image identical to the original. If we multiply the image down by 0.0001, even though we see a black screen here below, all the information is still there. If I bring in another Grade node and set its multiply to 10000, I effectively negate that colour correct. The result is identical to the original image. If I zoom right in I can see that there is no change between these two images.


Extreme color correction in Nuke, original

Multiplying by 10000, click to see larger

Extreme color correction applied in Nuke



Creating transparency is easy to do via masking in AE. If I want to draw a rough mask around the sky in AE. I hit G, simply draw out the mask and choose subtract from the mask's pulldown menu.

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Mask to create alpha channel in After Effects

In Nuke there is considerably more setup involved to apply transparency to an image. One important thing to remember about Nuke is that one needs to attach several discreet elements (nodes) together to get a result.

In AE the alpha math that creates layered composites is, for the most part, taken care of behind the scenes. In Nuke nothing is taken for granted. This ties in to my original analogy that in Nuke you have all the discreet elements laid out on something akin to a table in front of you, all of which you can see simultaneously.

Here is one way that I build composites with bezier based transparency in Nuke:

Create a bezier node followed by a copy node (both accessible from the menus on the left edge of the interface in Nuke 5).

Create the points of the bezier mask by option command (alt control) clicking in the viewer to create vertices.

If it isn't already, attach the bezier node to input A of the copy node and input B to the branch containing the image. In so doing you are copying the alpha of the A branch to the B branch.

Once the bezier has been copied into the stream that has the building we still see no change. This is because you have to explicitly tell nuke to premultiply the alpha. You need to add a premultiply node in order for us to see a result similar to what we saw in AE.

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Alpha channel via masking in Nuke

This setup in Nuke is clearly more work than doing the equivalent in AE but the benefit is that each element is visible in the node graph. In AE, although the setup is way simpler, it's much easier to end up playing the "what layer was that mask on again?" game.

Either way, it's not a big deal until your scripts/projects start getting complicated. Which bring us to the next part.



Similar results can be achieved in both Nuke and After Effects on any given shot. In my work I use them both, but for more complex compositing I prefer to use Nuke because of its “node-based” design.

If AE is like a stack of images, Nuke is like a table with all the images spread out. Each “image” would be a composition in AE. In Nuke’s “node tree,” the equivalent of an AE composition would be a branch comprised of several nodes. The benefit of the node-based interface design is that you can see everything at once.

For example, let’s say you have an unwanted roto mask pop on a certain frame. In AE, you might have to hunt it down inside a comp, inside another comp, inside another comp. In Nuke, however, you will likely be able to see the bezier culprit in the node tree immediately.

To better understand my analogy of Nuke as a table with everything laid out in plain view, I’d like to briefly show you a shot I worked on. It’s from the recent movie “Death Race,” starring Jason Statham and Joan Allen.

Below is a screen grab of the Nuke node tree of the entire shot from start to finish.

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Complete Node tree in Nuke

The big burgundy box is the starting point of the script where I have 'read in' the shot's plate using a Read Node. One thing that I really like about Nuke is that you can make little (or big) PostIt™ style notes for yourself (or anyone opening up your script) to help quickly navigate through it, like the note I added below, to mark the "In" point of the shot.

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Marking "in" point with a sticky note in Nuke

The director wanted a couple of helicopters coming in from camera left as part of the chase scene near the end of the movie.

The first thing that needed to be done was to clean up the background plate —there weren’t supposed to be any apartment blocks in the scene. This was done using tracking, bezier masks and sampling from clear parts of the sky.

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Background plate for "Death Race"

Further down the comp tree you'll see that this comp wasn't entirely made in Nuke, I went to AE to make helicopter blades.

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AE comp as a Nuke node

The blades that I rendered out from AE look like this.

AE render in Nuke node tree

The helicopter was a still that I found rummaging through the database. I created an alpha for it, and added some flashing lights and specularity using beziers.

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Helicopter from still for Nuke node tree

To the helicopter, I added a search light which was created in Nuke using the Volume Rays effect.

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Nuke Volume Rays effect


To create a reflection of the helicopter in the water, I flipped the animated helicopter, blurred in and used a portion of the rippling water as an alpha matte.

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Nuke alpha node

With that, I had a “finalable” shot, which is VFX lingo for a shot you can show the director that won’t make him/her upset.

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A "final-able" shot in Nuke

In AE, it would have been much more of a challenge to, for example, integrate the darks of the helicopter to match the sky. In Nuke, I used the ColorLookup node, and had to bring the dark helicopter values down into slightly negative territory in RGB space (which is still positive in Cineon color space).

AE’s Curves won’t really let you do this. It could be achieved in AE with the Levels effect in 32-bit mode, although with less accuracy.

Ironically, even though AE is a program that does a lot of calculation behind the scenes and is more user friendly, getting a good result doing the kind of color correction I am describing above requires a greater in-depth knowledge of floating point workflow and log colour space and than in Nuke, because Nuke is principally designed with Cineon-based workflows in mind. Cineon files are less a record of color intensity than light intensity, which allows interactions between layers in the comp to look much more realistic.

(Ed. note: Pete wrote a full article for us on the science of Cineons, especially how they handle light.)

Creative Cow Library: Cineons: What they are and how to use them



Here are a couple of my favorite nodes in Nuke that might be of special interest to AE users.


In AE the closest thing to ColorLookup would be the Curves effect. In both, the image is altered by manupulating points on a diagonal line. What I like about the ColorLookup node up is that it's infinitely zoomable, both in and out, and that you can manipulate points below 0 and above 1 along the curve.

Also, the values of the colours you sample in the viewer are plotted as vertical lines in the Colour Lookup Properties Panel. This is very handy for doing very accurate colour correction interactively.

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Nuke ColorLookup node


Nuke’s HueCorrect node (similar to AE’s Hue and Saturation controls) works well to reduce or boost the saturation of any specific portion of the color spectrum.

As with the ColorLookup node, you can sample RGB values in the viewer (see red rectangle on bus, above windowshield), and the sample’s hue value will be shown as a vertical line in the HueCorrect node’s properties panel.

This hue can then be reduced or boosted by dragging down or up a point on the horizontal green line in the center of the image. Super handy!

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Desaturation using the HueCorrect node in Nuke


Nuke has a super fast and very beautiful defocus node, which produces quite realistic circles of confusion.

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Nuke Defocus node for Lens Blur and Circle of Confusion



Nuke’s 3D compositiing environment is both exceptionally advanced and exceptionally well integrated into its overall toolset.

This also translates to integration with other applications: objects and sequences can be imported, transformed, relit, and motion blur applied based on camera matchmove data.

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Nuke 3D compositing


A very simplified example of this is shown below. Here I have mapped a sunset onto a portion of a sphere and used that as background for my scene, which would be rendered from a camera placed in the rough vicinity of the origin.

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Nuke 3D compositing with UV projection and camera

Objects can also have images UV mapped or projected on them, which lends itself to high-end set extensions that require camera projection in conjunction with solving for camera position.

Of course, yu can do some set extension in AE if you stay organized. Afew years back, I did several set extension comps for the film “Stranger Than Fiction” in AE. But working and rendering in Nuke is so much faster that I would have finished more quickly, and Nuke’s more advanced compositing would also have made it easier to integrate the finished effects into the scene.



Nuke supports EXRs better and more completely than any other compositing package. Understanding EXRs also helps understand some of Nuke’s advantages for handling every aspect of an image, and for organizing very complex compositions.

OpenEXR is a high dynamic range format developed by ILM, and now an open source format. An EXR has an unlimited number of 32-bit channels that can be assigned to a wide range of attributes — Z-depth, materials, motion, shadows, specularity, and so on. Nuke can read, process and write up to 1023 of these channels in a single stream.

This multi-channel workflow highlights a major difference between Nuke and other apps. Instead of having a huge tree with hundreds of nodes, I’ve been joining separate passes on 3D objects into one EXR. This makes it easier to map many channels, combined in a single node, to other nodes in one step. Of course, I still have complete control over every channel in that EXR, and can still individually map any nodes to any channel.

Bringing all of an EXR’s channels into a single node reduces the mess on screen, but to take advantage of all that power, you have to keep track of everything in your head a little bit, too. RGB channels show as black and white

You also have to get used to the idea that every channel — shadows, specularity, ambient occlusion, individual roto masks, etc. — is represented by a black and white image.

You can see this in Photoshop or After Effects, where the Red, Green, Blue and Alpha channels are all represented as individual black and white images that create blends of opacity and transparency — but you might be working with several dozen of those in a single Nuke node.

In other words, you have to get used to the idea of adjusting lots and lots of black and white images. In many ways, this is the essence of compositing: getting transparency right by visualizing it as a black and white image.

The advantage of this approach is that you have very simple tools to give you enormous power over a virtually unlimited number of attributes, to better integrate composited elements into the real world.



Another one of my favorite things about Nuke is that nodes are, in fact, plain text. If I select and copy any given node (in the example below, a Grade node), I can paste it to a text editor.

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Plain text for nodes and gizmos in Nuke


It works the same way for a group of nodes. When you put them together for a single effect, Nuke calls them “gizmos.”

At Mr. X, you tend to hear a lot of “Email me that roto when you’re done,” or “Send me that iDistort gizmo you made when you get a chance.” So if I come up with a cool recipe for, say, an edge detect, I just pass along the text.

I can also customize Nuke with this human readable code. I can change the way it looks, create custom buttons, sliders and plug-ins, set up batch rendering and make other repetitive tasks much easier, as well as make Nuke fit into any unique production pipeline. This can all be extended especially well if you have knowledge of a coding language like Python, which is now integrated into Nuke.

Nuke, from The Foundry


If you are an AE user and considering getting into high-end feature film compositing, Nuke is a great and fun option that’s fast becoming the feature film compositing industry standard. Nuke’s growth has already taken off, as all the major houses are already using it to some degree. In the next year, you’ll see virtually all high-end film work being done in Nuke.

Nuke is also affordable enough for most independent producers. To get started, The Foundry provides a free “Personal Learning Edition” for download, a great way to explore Nuke for yourself.

To hear more about Pete's experience using Nuke for film compositing, as well as how it compares to Apple Shake, be sure to check out his interview on the Creative Cow News Round-up podcast!


Pete O'Connell, film compositor and Creative Cow Nuke Forum leader Creativr Cow Master Series DVD: Advanced Rotoscoping in Adobe After Effects


Pete's past film credits include "Stranger Than Fiction," "Across the Universe," "Mr. Magorium's Wonder Emporium," "Just Like Heaven," and the highly acclaimed "Transporter 2." He is currently working on three 2009 releases for Mr. X: “Whiteout” (Kate Beckinsale), “Amelia” (Hilary Swank), and “Travelling” (Jennifer Aniston, Aaron Eckhart). The bestselling author of the Creative Cow Master Series DVD, “Advanced Rotoscoping in Adobe After Effects,” and host of the Creative Cow Nuke forum, Pete is also working on more tutorials for both applications.

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