What’s a node?

[Adolfo Rozenfeld]

Hello, Sandman.
Node based applications are based on a tree-like metaphor, where the different footage elements, effects and transformations are connected by lines. Its’ main advantage is that it allows you to define the precise order in which elements are applied how exactly they are linked. In AE, rendering order is usually changed by pre-composing (because that way you force items in the nested comp to be rendered before items in the “main” composition).

There’s no denying that for heavy effects and compositing workflows node editing is a potent metaphor inedeed! But it’s also true that there’s a bit of snobbery from a few users who try to put AE in the place of some sort of “toy” application. BTW, you can recognize these people by their frequent mention of 3D trackers and the use of the word “Comp” as if it was a verb (just kidding!!!).

AE on the other hand uses a layer based approach which a lot of creative professionals find very powerful for its’ purpose. Now (before AE 7 actually!) it became fashionable to dislike AE’s layer based interface, which is kind of silly if you consider it is such a succesful paradigm for all the things is does so well.

I think the tree metaphor can be great for example for the needs of Shake users, a very specialized application that excels at its’ task (and where few footage elements with very sophisticated processing is the most likely thing to happen). But I wouldn’t necesarilly see it the same way in Combustion, which just like AE tries to be a very wide application.

Finally, you know what? There’s a small bit of node based editing in AE in its’ Workflow window. It’s only a small bit, because it’s not really a manipulation tool, but just a visual reperesentation.

Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo@adolforozenfeld.com

[Andrew Kramer]

Think about a node as a machine. You put video through this machine and the machine changes it somehow.

Say I have a Color correction node (machine).

I put my video inside of the machine (node) and out comes the video with color correction. Say I have a green screen Node. The video goes into the machine and out comes the video with the green removed.

Now, when I set up the node tree I would run the my footage through the color correction node machine, then put it to the green screen node machine, then through another color correction node to enhance it further. Remember each Machine can be given unique settings.

Nodes are great for following the flow or structure of an effect with a single view of the node tree. (node tree the diagram of flow of the nodes. in this case you would see the initial color correction as one node and the outgoing video would link to the green screen node and so on until the render node etc.

In after effects it’s a little differn’t but similar in functionality for example when i add levels to a layer, then color key, then another color correction. It processes the effects in the order they are applied like would take place in a node tree.

Hope this helps.

[Andrew Kramer]

Nice Adolfo, you beat me.
lol
Andrew

[Adolfo Rozenfeld]

That happens to me all the time 🙂
That’s the bad thing about AE. The forum are so crowded! Maybe we should start using a less popular application!
All the best

Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo@adolforozenfeld.com

[David Frisk]

Thanks so much for your response.

So basically a node based application is just being able to have control over the render order?

What exactly do you mean when you refer to AE having a layer based interface? Are you referring to the layers in the timeline…or layers in terms of things being rendered in a specific order? If you’re referring to layers in the timeline, how do these node based applications interact? Wouldn’t they need some sort of “timeline” with multiple layers and things of that nature…or do they do things completely differently?

And lastly, why do people refer to masks in these other programs as being node based and being able to feather specific points? What does feathering specific points have to do with nodes?

Sorry if I’m sounding really stupid right now. I’m just one of those people that doesn’t like to understand something halfway. I feel the need to really get a grasp of it. Maybe you could give me an example of how a node based program would go about achieving some specific effect and how it is different from how AE would go about it.

Thanks again Adolfo and thanks to anybody that takes the time to walk me through this 🙂

[David Frisk]

“In after effects it’s a little differn’t but similar in functionality for example when i add levels to a layer, then color key, then another color correction. It processes the effects in the order they are applied like would take place in a node tree.”

This is kind of where I’m confused. Isn’t AE doing the same thing? You put one effect on it, and then that resulting video then is used when the next effect is applied, and then that resulting video is used for the next effect, etc?

Or does it differ because you have to worry about transforms being applied before effects and things of that nature?

[Adolfo Rozenfeld]

[Sandman] “Thanks so much for your response”

No problem.

[Sandman] “So basically a node based application is just being able to have control over the render order?”

It’s my understanding that this control of rendering order has much more to it. You could, for example, route effects independentlly of the footage elements they are linked to. So you could in theory crop a gaussian blur, instead of cropping a layer which had a gaussian blur applied before. Same thing for many other scenarios.

[Sandman] “What exactly do you mean when you refer to AE having a layer based interface? Are you referring to the layers in the timeline…or layers in terms of things being rendered in a specific order? If you’re referring to layers in the timeline, how do these node based applications interact? Wouldn’t they need some sort of “timeline” with multiple layers and things of that nature…or do they do things completely differently?”

Yes, I meant the layer based timeline. If you think about it, you already know applications that are based on timelines and still are not layer based. Editing applications, for instance, are track based, not layer based. Tracks exist independently of the clips you use in them. This is not related to node based apps, but shows that not all timelines are layer based.

My experience with that kind of interface tells me that timelines are not so so much about the visual stacking order of elements. They are more like AE 7’s graph editor, a place where you see keyframes displayed, etc. They usuallly have a separate Object window, where you see how objects are stacked. These applications are usually very context sensitive. You select certain object, and the timeline switches to animating properties for that object (again, like AE 7 graph editor). And you get spatial properties for that object in an Inspector window, etc. The one thing I would love to have in AE is what they call “Heads Up Display” (like war plane cockpits!), the ability to have parameters superimposed on the composition window for you to manipulate

Many of the things I am mentioning are more frequent in 3D applications, for example.

[Sandman] “And lastly, why do people refer to masks in these other programs as being node based and being able to feather specific points? What does feathering specific points have to do with nodes?”

You know what? Do those applications allow that control over masks because they are node based? Or because they are specialized compositing applications and then it makes sense for them to be node based 🙂

I don’t know if AE needs a node tree scheme to allow that. Probably it just needs an updated masking technology. I have no idea how or where they could display the feather values for each node, but hey, thank god I am just a user.

Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo@adolforozenfeld.com

[Chris Smith]

Here is a screenshot of Aruna’s Shake session for one shot in Hellboy. All of what you see are nodes. That would take a LOT of precomping in AE to do the same effect.

https://www.vfxtalk.com/forum/attachment.php?attachmentid=924

Every composite program I’ve ever used has awesome advantages. Just some are better suited for specific tasks. For FX, I only like node based.

Case study. You have a matte that defines an area of an image for a blur, color correction, and transparency of certain effects.

In a node tree you just pipe that output of the matte node to the mask inputs of the 3 effect nodes in question. Quick and simple. Sure you can solve your needs in AE, but in this case it would take a bit more planning and not near as flexible when you need to change something.

Yes, layer based meaning the main AE layers. Node based apps use a timeline with keyframes just like AE. But instead of having a ‘stack’ of layers that are always in order from top to bottom, you use a composite node of some type. For example, if you want to ‘screen’ something over another image in Shake, then create a Screen node. And pipe one input into it’s FG channel and the other into it’s BG channel. Then your output is the composite.

AE’s “Normal” transfer mode is the same thing as the ‘Over’ node in many composite programs. So when you create layers in AE they all default to ‘Over’ until you change the transfer mode.

The nodes in masks are also called points or vertexes (if 3D). In AE you can only blur/feather a mask globally. So when you feather the mask, the whole thing goes soft. If a mask allows you to feather based on it’s points, then you can offset points from their sister points to define a feathering amount. In AE you get around this by doing multiple shapes and feathering them differently if needed.

The nodes in most node based apps are very minimal. They do one very simple job and that’s it. For example in Shake, you have a Saturation node. That’s all it does. A Blur node, a pan node, a scale node, a fade node (opacity or level). Many of these functions are built into every layer of AE. So where layer based is awesome is when you are doing a ton of graphics, you don’t want to have to build the functionality of each layer from scratch every time. You would need a lot of nodes to equal the built in capability of just one AE layer.

In DS which is what I use, the nodes are extremely functional. Which threw me off at first because if all I wanted was to desaturate something, I felt gulity piping in an entire color corrector just to tweak one slider. But after I was assured that it only uses render time for what is tweaked, I really grew to like the DS nodes. Like it has a comosite node that basically has unlimited layers with opacity control and transfer mode change in one node. The color keyer has a built in tracker and matte shapes for garbage masking all built in to one single node!

So it’s just like a fork, knife, and spoon. Each system can be clearly argued to being better for a specific tasks. While at the same time they can all can be called eating utensils…er….compositors.

my 2 cents.

Chris Smith
https://www.sugarfilmproduction.com

[David Frisk]

Thanks everybody. Adolfo, Chris, Andrew, I very much appreciate you taking the time to spell this out for me. I understand now. Another thing to cram in my brain and hope it doesn’t push something else out 🙂

[Colin Braley]

In After Effects, you have a set rendering order (masks, effects, transforms, blend modes), and the only way to change this is pre-comping. In a node based app you have a web of footage and “operators” (things like color correctors and other tools) and you have more control over what order things are applied in. From my little experience with node based apps, I have realized that you can get things to render in any order without precomps like you would need in AE. Also, it can be easier to navigate through and understamd large projects in node based apps because you dont have to open a bunch of nested comps to find out whats going on. I’de say that is about how AE differs from a node based application like Digital Fusion.

~Colin