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[edit] Follow Path Constraint

[edit] Description

Follow Path places the affected object onto a curve object. Curves have an animated property that causes objects along the path to move. In order for this to work, you have to have the CurvePath option activated (it's a property of the curve object). You can find it in the Curve and Surface panel in the Editing buttons, F9.

The movement along the path might be controled by two different ways: the most simple, in this same Curve and Surface panel, is to define the number of frames of the movement via the num button Path Len:, and its start frame via the constraint's Offset: option (by default: start frame 1 (= offset of 0), duration 100).

The second way – much more precise and powerful – is to define a Speed IPO curve for the path (Path section of the IPO Curve window). The start position along the path will correspond to an IPO value of 0.0, and the end position, to an IPO value of 1.0. You can therefore control the start frame, the speed of the movement, and the end frame, and even force your object to go forth and back along the path!

If you don't want objects on the path to move, you can give the path a flat speed IPO curve (its value will control the position of the object along the path).

Follow Path is another constraint that works well with Locked Track. One example is a flying camera on a path. To control the camera's roll angle, you can use a Locked Track and a target object to specify the up direction, as the camera flies along the path.

This constraint does not work well with bones.

[edit] Options

Offset

The number of frames to offset from the "animation" defined by the path (by default: from the frame 1).

CurveFollow

If this option isn't activated, the affected object's rotation isn't modified by the curve; otherwise, it's affected depending on the following options:

Fw

The axis of the object that has to be aligned with the forward direction of the path.

Up

The axis of the object that has to be aligned (as much as possible) with the world Z axis.

In fact, with this option activated, the behaviour of the affected object shares some properties with the one caused by a Locked Track constraint, with the path as "axle", and the world Z axis as "magnet"…

[edit] Example

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Contents 1 Follow Path Constraint 1.1 Description 1.2 Options 1.3 Example