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Inspiring
December 25, 2017
Answered

Prevent snapping in camera tracking?

  • December 25, 2017
  • 2 replies
  • 1568 views

Hello.

I have a image that is attatched to a wall. I have done this using Track Camera. However, at some points, the image actually snaps to a new position to align itself.

Is there a way to make it smooth, over an interpolation if you will, instead of snapping?

    This topic has been closed for replies.
    Correct answer Roland Kahlenberg

    I don't really have any footage persay. But, to give an example, maybe this time it will be more clear.

    If I have a solid (image) being tracked with the video (on let's say a road). And it is a flat image or some decal or something. Let's say I was going really fast and each frame of the road made the road move a meter up. The decal, ideally, would move with the road the same meter up.

    Could I make it so that instead of it moving a meter up (and say the whole screen just shows 3 meters up to down), it moves instead 1/3 of a meter each frame or 1/4 of a meter each frame. It would still move in the same direction as where it should be, but half, a third or even a quater the distance.

    This is my third project in AE so I don't really understand half of your terminology when you reply btw. Thank you though.


    This tutorial author has close to 400,000 subscribers!!! He should not even be allowed to teach ONE other individual.

    There's just so much wrong in this video! The way he moved/adjusted the tracked target on the left wall immediately screwed up the accuracy of the tracked point. He's also not mentioned how to look for good and bad tracked points.

    To make the adjustments you want, I would look at parenting the layer to a Null. Then create position KFs to help you reach your goal. This process if of course done manually.

    2 replies

    Roland Kahlenberg
    Legend
    December 25, 2017

    Are you not able to read my reply?

    Very Advanced After Effects Training | Adaptive & Responsive Toolkits | Intelligent Design Assets (IDAs) | MoGraph Design System DEV
    Community Expert
    December 26, 2017

    If you change the keyframes for the camera you destroy the camera tracking solution.  There is nothing keeping you from animating the position of any 3D layers you place in the scene, It is just very difficult to keep them looking like they are attached to the scene. If you do not set an origin and ground plane to start it is almost impossible to figure out the 3D geometry.

    From your description, I think that you may be better off with Motion Tracking than Camera tracking. I'm still pretty much guessing about the shot you are trying to create.

    Mylenium
    Legend
    December 25, 2017

    Without seeing your footage nobody can advise. Such a behavior typically indicates that the camera is too close to the subject and therefore the orientation of elements flips back and forth. This may require extensive cleaning up of the camera motion more than anything else. A screenshot of the graph editor curve would easily reaveal such oddities.

    Mylenium

    Inspiring
    December 25, 2017

    For example, take the first few seconds of this video.

    How to Attach Objects to Walls & Ground in Adobe After Effects CC! (3d Motion Track Videos Tutorial) - YouTube

    You can see the top right video that is attatched to the wall is snapping a little bit when it repositions based on the camera movement. Is there a way to set that snap over an interpolation (just make it transition smooth to the new position?)

    Mylenium
    Legend
    December 25, 2017

    The camera in the example video simply has way too large a FOV and nothing was done to treat the footage to compensate for it. Or in other words: The tutorial is kind of rubbish and doesn't care to explain the prerequisites of a good track because the creator doesn't understand the requirements himself. And that's putting it politely. Any kind of tracking requires proper preparation and understanding how the underlying stuff works and it really is as simple as that. To eliminate drift and otehr oddities you have to know where you point the camera and use the proper technique like doing a manualyl calibrated track with lens compensation, which is not doen in AE simply because it's not supported. This requires tools like SynthEyes or other advanced tracking software.

    Mylenium