Look At Controller

The Look At controller is automatically assigned as a transform animation controller upon creation of objects that contain targets, including Target Camera, targeted lights (including IES Sun/Sky) and the Tape helper. It cannot be assigned by the user. To assign the equivalent of a Look At controller to an object, use a LookAt constraint.

Note: You can adjust the targeted object's pitch and heading indirectly only, by moving the target. The only orientation setting that you can control directly is Roll Angle (bank).

Example: To prevent flipping of targeted objects during rotation:

  1. Add a Target Camera object.
  2. Activate the Move tool and use the coordinate display to position the camera and target at 0,0,0 and 80,0,0, respectively.
  3. Add a Dummy object and position it at 0,0,0.
  4. Use (Select And Link) to link the camera to the dummy, and then link the camera target to the dummy. At this point, the dummy is parent to both the camera and its target.
  5. Rotate the dummy about its Y axis, and watch the camera.

    As the target passes through the zenith and nadir of its orbit, the camera flips.

  6. Select the camera and go to the Motion panel. On the Look At Parameters rollout, turn on Use Target As Up Node.
  7. Again, rotate the dummy about its Y axis.

    The camera no longer flips.

Interface

After you create or select an object that contains a Target component, you can access the object's Look At properties on the Motion panel. In this rollout you can change the target, create and delete animation keys, set the axis, and adjust other, related parameters.

Create Key group

Sets a position, roll (orientation), or scale key at the current frame, depending on which button you click.

Delete Key group

Deletes a position, roll (orientation), or scale key at the current frame, depending on which button you click.

Look At Target group

Pick Target

Lets you set a target other than the default Target object. Click this button, and then select the new object to use as a target.

Thereafter, the new target controls the object's orientation. The original target remains in the scene, and can be deleted or used as a Dummy helper.

Axis group

Specifies the local axis that looks at the target. The Flip checkbox is used to flip the directions of the axis.

Use Target as Up Node
When turned on, the controller forces the object on which it acts (source node) to keep one of its local axes aligned with the look-at direction (the vector between the source node and the target node). it also prevents the source node from rotating around the look-at direction, to avoid flipping about the object's local Z axis.

The flipping behavior is most commonly seen when the line between a targeted object and its target is close to vertical; that is, their positions on the World Z axis are nearly the same.

The option works by aligning one of the source node's local axes with one of the target node's local axes. These axes are picked automatically by 3ds Max.

Note: This feature lets you properly manipulate Luminaire assemblies. It also provides for trouble-free operation when you i-drop manufacturer luminaire assemblies.
Tip: In some cases, the object will flip 90 or 180 degrees even when Use Target As Up Node is on. This behavior occurs due to the fact that the axis alignment is automatic. To resolve this, apply a roll angle to the object with the coordinate display.
Position/Roll/Scale
These three buttons let you specify the other rollouts that appear for this controller. In all three cases, the Key Info (Basic) and Key Info (Advanced) rollouts appear. When Position is active, an additional Position XYZ Parameters rollout lets you specify the axis for which the Key Info rollouts show data.
Parent topic: Animation Controllers