72 lines
2.6 KiB
ReStructuredText
72 lines
2.6 KiB
ReStructuredText
.. index:: Object Constraints; Track To Constraint
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.. _bpy.types.TrackToConstraint:
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*******************
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Track To Constraint
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*******************
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The *Track To* constraint applies rotations to its owner,
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so that it always points a given "To" axis towards its target,
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with another "Up" axis permanently maintained as much aligned with the global Z axis
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(by default) as possible. This tracking is similar to the "billboard tracking" in 3D
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(see note below).
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This is the preferred tracking constraint,
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as it has a more easily controlled constraining mechanism.
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This constraint shares a close relationship to
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the :doc:`Inverse Kinematics constraint </animation/constraints/tracking/ik_solver>` in some ways.
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.. tip:: Billboard Tracking
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The term "billboard" has a specific meaning in real-time CG programming (i.e. video games!),
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where it is used for plane objects always facing the camera
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(they are indeed "trackers", the camera being their "target").
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Their main usage is as support for tree or mist textures:
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if they were not permanently facing the camera, you would often see your trees squeezing to nothing,
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or your mist turning into a mille-feuille paste, which would be funny but not so credible.
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Options
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=======
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.. figure:: /images/animation_constraints_tracking_track-to_panel.png
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Track To panel.
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Target
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:ref:`ui-data-id` used to select the constraints target, and is not functional (red state) when it has none.
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See :ref:`common constraint properties <rigging-constraints-interface-common-target>` for more information.
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Track Axis
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The tracking local axis, i.e. the owner's axis to point at the target.
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The negative options force the relevant axis to point away from the target.
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Up
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The "upward-most" local axis, i.e. the owner's axis to be aligned (as much as possible)
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with the global Z axis (or target Z axis, when the *Target* button is enabled).
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Target Z
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By default, the owner's *Up* axis is (as much as possible) aligned with the global Z axis,
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during the tracking rotations. When this button is enabled, the *Up* axis will be (as much as possible)
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aligned with the target's local Z axis?
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Target/Owner
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Standard conversion between spaces.
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See :ref:`common constraint properties <rigging-constraints-interface-common-space>` for more information.
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Influence
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Controls the percentage of affect the constraint has on the object.
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See :ref:`common constraint properties <bpy.types.constraint.influence>` for more information.
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.. warning::
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If you choose the same axis for *Tracking Axis* and *Up*,
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the constraint will not be functional anymore (red state).
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Example
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=======
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.. peertube:: 891bf27f-f782-4908-bfa0-f99e5dc46107
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