Up Vector Options

The up-vector constraint makes the Y axis of a constrained object point to a constraining (control) object or a specific point.

A typical way to determine an object's up-vector direction is to constrain it to another (control) object. You can do this by using the buttons in the Optional Up Vector Control Object area.

To set the up vector direction with no control object (known as a static up vector), set the Point At values below.

For more information, see Up-vector Constraints [ Animation ].

Optional Up Vector Control Object

These buttons allow you to easily see and change the up-vector values and relationships with the up-vector control object.

Select	Selects the current up-vector control object.
Remove	Deletes the up-vector control object but doesn't deactivate the up vector constraint (deselect Active to do this).
Pick New	Lets you pick a different constraining object. This also activates the Active up vector option if not already active.
Create New	Creates a little implicit cube (named upvctctrl) and uses that as the constraining object. It is placed according to the Affected Axis direction.
Active	Toggles on/off any up vector applied to the position.
Roll	Sets the roll value of the up vector.

Affected Axis

X/Y/Z

Sets which axis of the constrained object is to be the one used as the up vector (Y is the default). You can either click the axis buttons (positive and negative X, Y, Z) or enter 1 or -1 in the axis text boxes.

Point along Path Roll Frame Normal

Constrains the up-vector of the constrained object to the roll-frame normal of the curve instead of constraining it to a separate control object or direction (as defined by the Point At options). The roll frame normal is a frame based only on the moving tangent of a curve.

When you select this option, the Point At options become unavailable.

Because this option defines the up-vector direction independently from a separate control object or direction, this can help prevent the constrained object from flipping in cases where the trajectories of the curve and the up-vector control object would cross.

Point At

X/Y/Z

Sets the position at which the constrained object's up vector is to point. This allows you to make the object's up vector always point in a certain direction without using a separate up-vector control object. This is known as a static up vector.

If the up vector is constrained to a control object, the values shown here are the location of that object, and cannot be changed.