Skip to main content
Known Participant
March 30, 2018
Question

Drone Video -- Tracking Land boundaries

  • March 30, 2018
  • 1 reply
  • 1378 views

I am trying to use AE camera tracking to display the land boundaries.

This topic has been closed for replies.

1 reply

Community Expert
March 30, 2018

Step 1 is to remove any spherical distortion in the shot, then pre-compose or render a digital intermediate using a suitable mezzanine codec (NOT an MP4).

Step 2 is to break the shot up into short segments that are just long enough to include one or two of the features you want to track while they are in the frame.

Step 3 is to camera track each segment of the film, set an origin and ground plane and then attach placeholder solids to geometry in the scene. It is a really good idea to add a grid to the placeholders to make sure they are firmly attached to the geometry in the scene. If you have hills and valleys in the footage or other structures in the shot you'll need to attach a placeholder solid to each surface so you can create track mattes or adjust your illustrations to fit the terrain. This can get very complicated in a mountainous area. Empty flat fields are pretty easy.

Step 4 is to create the illustrations for your land boundaries. If the land is flat you can just trace a plat map. If it is hilly then you will need to make adjustments to account for the terrain.

The last step is to set your illustration layers to 3D layers and then hold down the shift key as you parent them to their placeholder solid and then turn off the placeholders or make them guide layers. A final tweak of the Y rotation may be necessary if you have not precisely lined up the placeholders.

That should do it. It is all pretty straightforward if you are familiar with AE's 3D space, camera tracking, and parenting. I cannot overemphasize the need to trim your footage so that you have one shot for each object that needs to stay in the frame because AE's camera has no distortion and almost all drone footage does so the track is going to fall apart as your placed illustration approaches the edges of the frame. You can re-assemble the entire shot if you need to later.

I hope this helps. If you have not done any camera tracking or lens correction before you will need several hours of study to get up to speed. If you are new to the process it would really help us to see one of the shots you are trying to work with.  If you have no idea what a mezzanine codec is then you should study up on video formats.

maher55Author
Known Participant
April 4, 2018

Hi Rick,

I've done a lot of trial and error today. The tracking points are ok. What is occurring is that the starting postion of the beam effect disconnects from the null object.

I wonder if the beam effect has a limit to how far it can be stretched. I'm thinking I will try your suggestion of using the pen tool to draw directly on the shape.

So using this suggestion I would just place a solid object inside the land boundary and use the pen tool to create the are boundaries.


Thanks Rick for your time. I am trying to get this down pack. Like to start using After Effects in my drone videos.

Community Expert
April 4, 2018

Beam is a lousy way to try and draw anything but a straight line. I don't know what you mean by disconnecting from the null. That sounds like user error.

To draw directly on a frame you start by establishing an origin and ground plane, then adding a placeholder layer with grid added to make sure that your origin and ground plane is accurate. Then you just add a new shape layer. It will have nothing on it. Then you make the layer 3D, hold down the shift key and parent it to the placeholder solid. This shifts the shape layer to the exact same position and orientation as the placeholder layer. The last step is to just grab the pen tool (g) and start drawing a path using the video as a reference.

If you have a good camera track everything you draw should stick to the footage perfectly. If it does not stick then you did not check the Camera Track and verify that the placeholder was locked to the ground.