As some of you may know, when it comes to rotoscoping, there are two core software solutions that studios integrate into the vfx pipeline. The first and probably most common being Nuke, used by studios such as Animal Logic and the other being SilhouetteFX, used by studios such as WETA VFX. So I thought that I would do a comparison of the two tools to establish which is the better software to learn (or simply to learn first)…
Firstly to compare these programs a distinguished definition of what a roto/prep artist’s responsibilities are is necessary, so i have broken it down into several key points:
- 2D tracking
– Matte extraction
– Rig removal/paint fixes
– 3d camera projections
– Clean plate creation
– Spline based roto creation
So to compare these two packages I have broken down this comparison into 5 categories, layout, rotoscoping, tracking, keying, paint and stereoscopic workflow.
LAYOUT & WORKFLOW
When comparing the layout of Nuke and Silhouette there are two very obvious differences. One is node based (Nuke) and one is layer/node based (silhouette).Immediately this really makes Nuke a clear winner with just this fact alone as the more fundamentally node based a compositing-roto package is, the less linear it is and there for the easier it is to trouble shoot and faster the program will be. However, in saying that, it would be unfair to immediately declare Nuke the winner based on this alone as we are not talking about these two programs in the context of compositing, but in the context of being a roto/prep artist which really changes the essence of what is important in the layout.
- Nuke’s default layout
- Silhouette’s default layout
- Nukes ability to save layouts
The first thing that you will notice when opening Nuke is its distinctive and simplistic layout, the beauty of this layout is that it can be customised anyway you want and is extremely maneuverable depending on your workflow. It also allows for layouts to be saved depending on what sort of tasks you are performing. However Nuke’s beauty can be a little cluttered and counterproductive without multiple screens, this is only a slight draw back though as you can expand a screen your using (whether its the viewer or node graph) by a simple hit of the space bar.
Now to compare this with Silhouette, on opening you everything is laid out neatly, when beginning a new project it will ask what particular nodes (or functions) you will be using for the course of the project (whether its keying, roto or paint ect.). This is a nice function and its also notable that a single screen setup for silhouette still works really well as everything is ergonomically placed. The down fall of the silhouette layout is its limited customization options which is understandable given its not used for anything other then roto and prep work.
- Silhouette’s “node” layout
Now for node ease of selection it Silhouette is instantly a clear winner as all the essential nodes for roto/prep are directly available without any need to search for them like in Nuke. This does increase work flow efficiency as you can quickly start using a node without searching for it in a drop down menu like Nuke’s. Of course in Nuke hot keys are available as does silhouette, however the difference here is that all of the essential nodes in silhouette have hot keys available, which is simply not the case in Nuke. However in Nuke it is possible to re-assign the default hot keys, but it is a painful process.
One huge down fall of Silhouette is the fact that you can’t import video files, unfortunately you are limited to only using sequences, now this was an issue with Nuke as well back in the day but they realised the need for video as well as sequences, something the silhouette hasn’t managed to modernize itself with.
- Traditional colour check set up for Nuke
Another aspect of silhouette’s layout that rises above that of Nuke’s is the ability to do colour defined roto/key quality checks (e.g. having a red overlay where the alpha is to check that the roto/key is covering whats intended for the duration of the shot) with ease. In the case of silhouette all that is required is the simple hit of a button from number pad to switch between these checks and views. I do realise that this exact thing can be done in Nuke and some would argue is better as you can define what number press effects each of these views, but the difference is this viewing method has to be set up in Nuke prior to being able to do this with the use of several nodes,
but in Silhouette it is ready at startup. However in saying all this, the huge downfall of Silhouette is that you can’t actually create custom channels, you are restricted to RGBA. Ofcourse most of the time that’s all you need, however it can be handy to do multi-channel roto passes when compositors have specific needs for your roto.
ROUND 1 VERDICT: NUKE
So in summary, although Silhouette has a lot of efficient and ergonomic designs for setting up and executing a roto comp. The fact that Nuke is so non-linear and customisable makes it a winner regardless of what hot keys and viewing options Silhouette has to offer.
Now to judge whats really the most important part of a software package for a roto artist: how well you can roto with it.
- Nukes roto tools
Let us start with the roto tools available in each of these two packages. Firstly in Nuke the roto menu has 4 shaping options: Bezier, B-spline, Ellipse and Rectangle. These four are really all you ever really ned for doing your shapes, however there really is no harm
done in having more. Which is exactly where Silhouette comes in where there is in fact an extra type (also found in after effects) called the X-spline. For those not familiar with this it is basically a more maneuverable version of the bspline, with every point you make being a transformable one.
- Silhouette’s limited roto options
Now when it comes to the actual roto node options for each program, there are some rather large differences, and by this I mean Nuke is so much more flexible and non-linear. Now these differences start with the blending options for each program. Silhouette features the basic Add, Subtract, Multiply and Difference blending modes, and whilst this is generally all you need, it never hurts to have more options. Nuke on the other hand has the option to do all these, as well as the option to merge: atop, average, colour-burn, conjoiunt-over, copy, disjoint-over, divide, exclusion, from, geometric, hard-light, hypot, in, mask, matte, max, min, minus, out, overlay, plus, screen, soft-light, stencil, under and xor. Although most of these wouldn’t be used often for roto, it is good to have, and I find myself often merging with Stencils, Max’s and Disjoint-overs.
Next up with the roto options, where Silhouette has all the basic shaping modifiers like blur, erode, opacity, invert and channel options. Nuke in fact has all these plus foldering options, multiple layered transform options, shaping options and even the ability to determine the lifespan of a bezier without effecting its opacity.
Lastly the actual performing of the roto and animation of the roto: arguably the most important aspect of this whole review. However when it comes to this, the two programs work pretty much exactly the same, the major difference is with the timeline. In Nuke each key frame that is made for a roto shape appears as a blue mark on the frame in the timeline that the change occurs. In Silhouette it works exactly the same, however with Silhouette the time line shows the key frames for each separate roto shape as different layers, compared to it all being dumped together. This is really helpful allowing you to instantly see which key frames are associated with each different roto shape. Now of course this can be done in Nuke, but for this to be done you either need to have the dope sheet constantly open in some corner or you need to keep flicking between it and your node graph, neither of which are very efficient or ergonomic.
ROUND 2 VERDICT: NUKE
Although for the animating and drawing of shapes in each package is the same, nukes huge amount of modifiers and options make it a clear winner in this category.
Regular joe’s often get confused when keying is mentioned for roto jobs, but as any roto artist would know: if you can’t key it THEN you roto it. There’s often times where you can key something out that will give you the smooth animation and edge fidelity that rotoing by hand or with trackers can never provide.
- For example to get an alpha channel for the horizon, its much easier to simply pull a luma key on a shot like this over rotoing everything.
So lets start this comparison by looking at what different options we have for keying in each program. In Nuke, the main keying nodes (and I do say main as there are more) are:
- Keyer: which is the most basic keying node, featuring your different types like: green, blue and luminance.
- Key light: a very advanced keyer that is great for getting accurate edge fidelity, yet lacks in getting the alpha perfect across the whole key.
- Ultimatte: is a very advanced keyer that allows for maximum control without the need for multiple nodes, in fact I believe ultimate has the most options out of any node inside Nuke.
- Primmatte: The easiest and fastest keyer for good results. The beauty of primatte is its ability to add more than one colour to the key. You can basically keep picking more and more colours you want to remove and more colours you want to keep from you footage until you have the exact key your after. It is also very effective for marker removal work.
In Silhouette there are only two nodes for keying, these are:
- Keyer: very similar to that of Nukes “keyer” node and in fact has indistinguishable results.
- Power Matte: is a very cool, effective and simple gem that Silhouette has over Nuke. Silhouette’s matte chops don’t end there. Power Matte puts a little magic in your workflow. It’s similar to that of the Rotobrush in AfterFX’s, but using roto shapes for each area you want to keep and remove instead of painting the areas. However although its like AE’s Rotobrush it really can not be compared, Silhouette then automatically generates a high quality matte even on intricate details such as hair and fur. What makes this keyer so cool is that you can key frame and animate the roto shapes (being used to key colours and luminance) as the shot goes on for a very effective result.
- Power Matte in action!
With all this being said it probably sounds like Nuke is a clear winner for its abundance in keying options, but a very important aspect of keying that has to be mentioned is the combination of keys. It is near impossible to get an effective key of something with only one type of key, even when its a blue screen being keyed it’s often the case that lighting will be different on throughout the blue screen
- Silhouettes multiple pass key
forming different shades of that blue and thus for the perfect alpha channel, different keys need to be combined.
With Nuke this is done through using different merges like the multiply to combine the alpha channels of each, in fact to get a really good key a lot of different nodes need to be used from time to time. This of course means that its not always fast and simple to get the matte that you are after. However with Silhouette it is very easy to combine keys (to an extent) as it has the option in the keying node for primary and secondary keys as you can see on the picture to the right.
In saying that, the problem with Silhouette is you are limited to exactly that: two passes of keying. Whilst its layout makes it fast and easy, this can be very limiting as you can simply continue to add more and more passes to you key until you have exactly what you are after. Further on this, Silhouette is also limited by the fact that you can’t choose the exact colour you want from your footage, your locked into the basic realms of its standard blue and green screen defaults.
ROUND 3 VERDICT: NUKE
Once again Nuke takes the cake for the same reasons: flexibility!
When performing a matte extraction the first thing to always keying, however when roto becomes necessary the next step is to try and make life easier in any way possible. That’s where these bad puppy’s come in!
- Nothing better then MOLE-estering a facial feature to track
Nuke has two core 2D trackers:
- Tracker: The tracker is Nukes default 2D multi-point tracker. It does all the basics like Stabilization, Matchmoving, jitter removal and channel controlled tracking.
- Planar Tracker: A plane based motion tracker that uses a roto shape you make to judge a plane and follow its movement. It can provide very accurate and jitter free results in those times when you just cant get a movement right. A very hit or miss tracker.
Silhouette also has the same two and has pretty much all the same features as described for Nuke above. However differences can be seen in the Planar Tracker, where Nukes tracker forces you to sit there and watch the tracked area it captures for each frame in the form of a point, Silhouettes actually allows you to see inside the roto shape and indicates where areas are being tracked well (green) or could cause problems (red) like that of 3D camera tracker. It then allows you to disable certain points that are considered defective (red).
- Silhouettes planar tracker in all its glory!
Putting these two trackers together on the same 26 frames of footage resulted in very similar results. However in saying that, Nuke seemed to handle the point tracker better and smoother (slightly) and had less random pops, also applied stabilization more effectively. But Silhouette masters the Planar tracker with better results more of the time. Although in Nukes planar tracker a separate tracker node can be generated, it still doesn’t compare to Silhouettes often flawless tracks.
To a roto artist, having access to camera’s, axis/locators is invaluable, it can literally allow you to do one frame of roto for a very complex large duration stereo shot and have the whole thing animate and correlate perfectly.
This is the biggest reason why Nuke is better than Silhouette:
- Nuke allows you to import camera’s tracked in different programs
- Nuke allows you to perform 3D tracks in the program itself
- Nuke allows you to import and create axis points (Points to 3d)
- Nuke allows you to project roto and paint onto cards
- Silhouette can not work in 3D space at all or use any cameras.
For such a large and helpful tool to be missing from a roto software package is beyond me but that is why…
FINAL ROUND VERDICT: NUKE
This post is still a work in progress, to be continued…