The Motion Tracker object has a similar option (see Lock Solved Data). The activation of the Lock Solved Data option analogously: if enabled, the successful 3D object solve will be maintained, regardless of whether or not the object Track or other settings are modified. Otherwise the object reconstruction (Object Tracker animation and generation of the 3D features) will be deleted.
Settings for Geometry-Assisted Object Tracking
This and the following options are only made available if a geometry-assisted solve is done. If this option is enalbed, Cinema 4D will assume that all solved features (the Null objects in 3D space) must lie exactly on the surface of the refernce object and will be solved accordingly. The reference object must be positioned very precisely.
If this option is disabled, a certain degree of flexibility is allowed and the solved features can diverge somewhat in their orientation from the surface.
Generally speaking, the following should be noted:
Often, this is how the best results can be achieved since it is fairly difficult to position the reference object precisely.
Note that all (feature) Null objects will be colored white if this option is enabled because there is no doubt about their position (they lie on the reference object’s surface). Therefore, it is not necessary to use the red/green coloring to display how certain Cinema 4D is about their position.
Especially when using very few Tracks it can occur that a solved object rotates unexpectedly (the algorithm will have found 2 valid rotation directions and cannot determine which one is correct). If this happens, this option should be enabled. Otherwise this option should be left disabled.
Clicking on this button will start the solve process.
This button will be grayed out and not accessible if:
If the 3D solve was successful, the Object Tracker object will be assigned position and rotation tracks that will represent the object movement. Also, if a solve was successful, the calculated features can be made Child objects as Null objects of the Object Tracker object (separated into Auto and User features; furthermore, red and green colors will be used to show how certain (green) or uncertain (red) Cinema 4D is about the quality of the features). You should already be familiar with this from the 3D camera solve. These features can be used to position inserted 3D objects (which should then be made Child objects of the Object Tracker object).
Any reference objects used can also be made Child objects of the Object Tracker object. This makes it possible to get a good impression of the quality of the object solve while the animation is playing.
It’s possible that only parts of the object can be solved if too few Tracks exist for the entire sequence. This can be seen in the Object Tracker, which will not be equipped with keyframes over the entire course of the sequence. Additional Tracks should then be added in regions with too few keyframes.
If the 3D object solve was not successful (a corresponding message will appear in the status bar), either too few or bad Tracks will most often be the cause (see also What are good and bad Tracks?).
For non-geometry-assisted solving it is theoretically possible - with enough Tracks of adequate quality and a properly positioned object - to also calculate the focal length (it will have one keyframe). However, in most cases it is recommended that the focal length be calculated using the proven 3D camera solve since it often offers better conditions (more Tracks) for good camera solving. In this case, each subsequent object solve that is base on this will use this focal length anyway (linked Motion Tracker and Object Tracker objects use the same camera).
In the event that absolutely no focal length is known (note the Camera Calibrator tag in conjunction with this, which can be used to calculate focal lengths) or can be ascertained, the focal length can be estimated or omitted altogether. However, the probability that you will get a useable solve is not as good.