Trying to understand AE concepts

[Daniel Waldron]

That’s a pretty advanced tutorial for an AE beginner 😉

The 3D camera tracker replicates the camera movement in your footage and creates a new camera in After Effects. This is the layer you are seeing. It won’t appear to do anything until you add a 3D layer into your scene. Then the layer will react to the After Effects camera like it is a part of the scene. I would definitely go over the basics of AE before trying to attempt something like this. Though a little dated, I think Video CoPilot’s Basic Training is a good place to start.

[Todd Soaper]

Daniel, thank you, much appreciated. Will look into the training you suggest.

PS: Although new to AE, I am a seasoned software engineer, so I just jumped into the tutorial in question, but you’re right, I should look into the basics first.

[Todd Soaper]

Daniel, one additional clarification if you could – you say:

> Then the layer will react to the After Effects camera like it is a part of the scene.

What layer does the reacting, the 3D camera tracker layer, or any new 3D layer later added into the scene?

Thanks again.

[Todd Soaper]

Also, is the 3D camera tracker the only camera in the scene? Thanks.

[Daniel Waldron]

Any 3D layers you add will react to the camera. The 3D camera tracker should be the only camera in the scene.

[Todd Soaper]

Daniel, thank you.

[Todd Soaper]

Dave, thanks, your comments give me the necessary clues! Some things in AE just did not make logical sense to me. In light of your comments, the situation is now becoming clear. I am thinking that there is probably a lot of technical debt in AE.

[Walter Soyka]

[Todd Soaper] “Dave, thanks, your comments give me the necessary clues! Some things in AE just did not make logical sense to me. In light of your comments, the situation is now becoming clear. I am thinking that there is probably a lot of technical debt in AE.”

The Ae development team is doing a lot of refactoring right now, specifically catching up on loads of that technical debt, while trying to minimize changes to the user-facing parts of the application.

But that’s not why things don’t make sense to you. You’re just not familiar with Ae yet.

Ae is pretty consistent internally, but you have understand its data model. With your limited exposure to Ae, you haven’t yet seen enough to be able to correctly intuit what’s going on under the hood.

To answer some of your specific questions:

[Todd Soaper] “To do camera tracking, you do this:
1 – Animate->Track Camera
2 – Analyze/Solve
3 – Create Camera”

Track camera is available in the animation menu for the sake of consistency; the other trackers (which are not effects) also live there.

[Todd Soaper] “And although this layer is created from within the Effect Controls panel, the panel is not displayed when the 3D Tracker Camera layer is active!”

The Effects Control Panel is an inspector that shows all effects applied to the currently-selected layer.

The 3D Camera Tracker is an effect, which allows it access to the layer’s image buffer and gives it a place to store its tracking information as a custom data type.

Because the 3D Camera Tracker effect lives on the footage layer, it does not appear on the 3D Tracker Camera layer, even though the effects created that layer. It would be inconsistent with the behavior of the ECP and the expectations of the users if the effect appeared on both layers.

I swear, this all makes perfect sense when you know Ae really deeply.

Adobe in general seems to recognize that their applications have complexish architectures, and they strive to keep things as consistent as possible over the course of a few years for their users, adding features within existing frameworks where possible. The alternative — constantly refining the major frameworks to accommodate new features — would have dire consequences for cross-version compatibility and would require significant user re-training for each release.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive   |   RenderBreak [blog]   |   Profile [LinkedIn]

[Walter Soyka]

[Daniel Waldron]“Then the layer will react to the After Effects camera like it is a part of the scene.”

[Todd Soaper] “What layer does the reacting, the 3D camera tracker layer, or any new 3D layer later added into the scene?”

I wouldn’t say that layer reacts to the camera. Rather, I would say that the renderer draws the 3D layers from the perspective of the active camera.

A couple quick notes:
1) This is a slight oversimplification. There are limitations to lighting and layer intersections when you mix 2D and 3D compositing.
2) You can have multiple cameras in a comp, but only one can be active at at time.

Remember that the point of the 3D Camera Tracker is to figure out how the camera was moving in real space and give you a virtual camera that matches that movement. Your footage layer is still 2D, but you can now add 2.5D objects into the scene and have them in the same 3D space/camera move as the footage.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive   |   RenderBreak [blog]   |   Profile [LinkedIn]

[Todd Soaper]

Walter, thank you. Your notes are a valuable resource for me. Thanks for taking the time to reply.

You say:

> Ae is pretty consistent internally, but you have understand its data model.

How can I go about this? I know that a comp is fundamental to AE, and that layers live inside comps, and comps may also be nested in other comps. But my knowledge ends there.

You mention 2.5D. Never understood what this means. I read the Wikipedia article, watched YouTube videos that animate still pictures. I understand that much. But, for example, what is a “2.5D bounding box”?