2017

Setting the Scale
After tracking has occurred, you can set the scale of the tracked object. Since you are tracking a specific
object as part of an image, setting the relative scale of the object in relation to the image helps you to position
objects in the reconstructed scene when you convert the 3D points into a point cloud or axes.
Refining or Updating the Track
Once you are satisfied with your fine tuning changes, you can refine or update your Analyzer.
To refine or update the 3D track:
1 Depending on the changes you have made, you can choose to refine or update the 3D track. Do one
or both of the following:
■ Click Update.
NOTE The update operation deletes all previous 3D points and starts over based on the new information.
Depending on your footage, and how many trackers you added, deleted, or linked, multiple updates may
yield different results.
■ Click Refine.
The track analysis uses the current results as a starting point, and refines from this point.
Click Refine again to stop the process once an acceptable pixel error value is reached. The pixel error value
is a representation of the distance of the 2D tracks from the computed 3D points.
TIP The refine process is footage-dependant, so your acceptable pixel error value may change depending on what
is tracking. Since the refine process continues until you stop it, as a general rule, if the pixel error value does not
change for a length of time (for example, 30 seconds), you can stop the refine process. The lower the pixel error
value, the more accurate the reconstructed track is.
Converting Object Tracking Results
When you are satisfied with the results of the 3D object tracking analysis, you can convert the selected
reconstructed points to a point locators object or actual axes in your scene. The point locators object is useful
because you can easily snap objects to the locators. An image that does not deform is the best candidate for
the point locators.
666 | Chapter 15 Compositing in 3D Space with Action