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Keying and Hierarchies
The GeoH panel's Key button has some carefully chosen wrinkles to simplify its use with entire object hierarchies. In this section we'll describe what is happening in some more detail. The quick version is like this:
- Turn Key on to say this tracked frame is good, track later frames based on this data.
- Turn Key off to say this stored data isn't that good, or something else changed, so dump the stored data and retrack this frame using earlier reference data. When later frames are retracked, they'll use the earlier reference data too.
The Key button's functionality is designed to give a reasonable version of that even when entire hierarchies of objects are involved, without forcing you to click through each individual child object, which would be a pain. It's a good idea to understand what it's doing, in case you need to do something a little different.
Here's what's happening behind the scenes, starting with the data being affected:
- The "key frame" track, ie "GeoH Key frame" in the graph editor. This track marks individual frames, when a frame is keyed that means that this frame's image should be used as a reference for tracking subsequent frames, and it forces the object's joints to be locked to their lock values on this frame, regardless of the Locked buttons.
- The 6 "Locked" buttons, XYZ,Pan,Tilt, and Roll. When set, the corresponding joint is locked to the lock value, when not set, the joint's value is determined by the tracking. These buttons are animated tracks.
- The 6 lock values (spinners). These are the values that joints are locked to, either by the Locked buttons or key frame track. These are animated values.
The Key button affects all of these indirectly, depending on the situation.
When the Key button is off, and you click it ON , the following happens. A key is added to the key frame track for the current frame. Lock value keys are added for the current frame for each unlocked joint, locking the joint to its current, as-tracked value.
This is repeated for each child, and child's child, of the current object. It is also repeated for each parent, and parent's parent, of the current object (but not any parent's children!) because you can't count on the current object's results if its parents can change.
When the Key button is on, and you click it OFF, the following happens. The key is removed from the key frame track on the current frame. Lock value keys are removed from the current frame for each unlocked joint. This is repeated for each child, and child's child, of the current object. It is not repeated for any parent objects! If you think of a body with two arms, if you unkey the left arm, you don't want to unkey the body, because it may need to still be keyed for the right arm! If you need to unkey the body, you can do it automatically.
Control-clicking the Key button on or off performs the operations above, but none of the children or parents are ever affected—only the current object. This is an override for expert use.
Right-clicking the Key button removes the key from the key frame track, but does not remove the keys on the lock value tracks. You might want to do that if you will turn on the Locked buttons to hand-animate while the object is occluded, for example, but you don't want it marked as a key frame because the imagery isn't useful as a reference. Only the current object is affected.
Control-right-clicking the Key button truncates all following key frames from the key frame track. This affects only the current object. You might want to use the graph editor instead.
While the details of this button go on for a while, most of the time you should be able to just click it on or off.
©2023 Boris FX, Inc. — UNOFFICIAL — Converted from original PDF.