2009

Scene object Associates a tracker with a scene point object that corresponds

to the image feature in the Movie window. Pressing this button puts 3ds Max

into standard object picking mode. When you’ve selected the object, the entry

in the tracker list and the text in the button change to the name of the selected

object. You can change the connected object at any time by pressing this

button.

It’s recommended that you use point or CamPoint helper objects, although

you can use any 3ds Max object. The tracker uses the pivot point of the selected

object as the correlation reference point during the match computation.

When you set up a tracking project, you can make the tracker save the setup

in a .mot settings file. The association between tracker and scene point object

that you set up here is saved as a scene object name. If you reload the movie

in the tracker, the object association is reestablished using the object's name.

This means you must be careful to name the point objects uniquely, otherwise

you might establish incorrect associations. Further, you must load the working

scene in 3ds Max before opening the movie in the camera tracker utility, so

the named objects can be found. If you happen to open the movie first, the

object names in the Tracker list will all read "<none>". Simply reopen the

movie in the tracker and it will establish the connections correctly.

Match weight Sets the camera matching priority separately for each tracker.

Use this to improve the match accuracy for features close to where a computer

graphics generated element will be inserted. It helps to minimize sliding and

jitter in that part of the scene.

The match-move algorithm works by adjusting the camera to minimize the

error between the feature objects seen through the camera and their associated

feature points in the movie plate. With all weights set to 1, the algorithm

randomly distributes the error between all the object projections and their

tracking features. If you bump the Match Weight of a tracker, it redistributes

3832 | Chapter 15 Animation