Get Velocity vector length wrong if actor is animated along spline in sequencer

Hi Guys,

I’m trying to get a vehicles wheels to rotate proportionally to the vehicles speed when the vehicle is animated with sequencer rather than as a vehicle pawn. I tried to record sequnces as a pawn but they didn’t work [properly and I saw that other users had same problem.

My solution which works for non spline based animations is to assign vehicle mesh to BP, get ‘Get Velocity’ and use vectors length , divided by some value, to determine the wheels (additional meshes) ‘Add Relative Rotation’. Plonk actor at point A keyframe then drag to point and keyframe and it is all hunky dory.

Unfortunately, however, if I try and the actor to follow a path from a spline BP the Velocity vector length bears no relation to what the actor is doing.

Any help would be greatly appreciated.


Its not wrong, speed is relative.

It has to do why how you make the vehicle move along the spline.
If you just set its position, then velocity is always 0.

You also may be better off just animating the twist. This would be similar to how you do steering wheel rotations.

Take the overall distance because you know what it is off the spline. Divide it by the wheel diameter, because that the number of rotations you need to have over time.
and you can go from there.
In a perfect, animated, newtonian world. Being an animation I doubt you need to be more precise than this.

When I say go from there.
take the time of the shot that you want the car to travel for, divide it by the number of rotations, and implement a custom rotator or animate the wheel to rotate at the rate you get that way.