Multiple objects following the same path at different rates

I'm trying to set up multiple objects to follow the same Path. To achieve this I have created a NurbsPath and manipulated it into the desired shape and added multiple objects (spheres) with Follow Path object constraints with Target set to the NurbsPath.

For a single object to follow the path I would simply set the NurbsPath Path Animation properties and keyframe the Evaluation Time to vary between 0 and the value of Frames. This would animate the object along the path (in this case it's 52/100th of the way along the path).

Animating multiple objects along the same path at the same rate is not a problem as each object's Follow Path constraint can be set with a different Offset to offset the animation by the required amount.

The problems comes with changing the rate of the animation. Since the Frames and Evaluation Time are properties of the Path I don't see how this can be achieved - other than Duplicating the path and changing the duplicate path to have different Path Animation settings to set a different rate. This seems messy - especially if the path needs to be adjusted as both paths would need to be kept in-step.

(the above animation was achieved by having 3 paths, each with different Path animation settings)

Is there a better way of achieving this? ie, without needing multiple duplicate Paths.

• This is one of the best-redacted questions I have ever read on any stack exchange page. – Rafael Feb 5 at 20:09

With just a follow path constraint, with fixed position set to True, an offset of 0 is start, 1 is end of curve. The offset can be keyframed / driven.

Sample file, 3 cubes, All at 0 offset at frame 1. Two are keyframed, one traverses path in 50 frames the other 80 with an offset value of 1 at those frames respectively.

The other is driven by the frame number

(frame - 1) / 100


which will be at 0 at frame 1 and 1 offset at frame 101 and above.

• Thanks - that works like a dream. Didn't realise that Fixed Position worked like that (seems a misleading name for it so I never thought to mess with it). – Rich Sedman Feb 1 '17 at 15:22

Instead of keyframing the path "Evaluation time" property, you can add keyframes to the "Offset" value in the constraint panel. So every sphere has its own constraint, with its own Offset value!

• Thanks - that does seem to work - although the Offset needs to be manipulated backwards (so, say, -10 would be a tenth of the way along a path that was 100 "frames" long. – Rich Sedman Feb 1 '17 at 14:46
• Yes... I saw it. Maybe this can be solved reversing something (the path direction, or something else... Don't know). – mugnozzo Feb 2 '17 at 18:20