Keyframe interpolation question

Is there an option to have a point (or camera, or anything else) move from keyframe to keyframe without 'wobble' on the position property?
eg. If I have three keyframes creating a triangle. The first two points are along the base and the third is above them in the middle. When the point animates between the first two points is moves off the line to go around point 2. Like a car rounding a corner.
I have all the points set to "linear". (I thought that Smooth would give that effect)
But I have found that both linear and smooth travel the exact same path. The only difference is that smooth has the speed changes.
If there any option to just have the point tween directly from keyframe to keyframe? Or is there something I can do to achieve that effect?


  • AxelWilkinson
    AxelWilkinson Posts: 5,259 Staff
    edited September 2011
    This looks like a bug to me, I'll look into it further and see what can be done to fix it. In the meantime, if you copy your middle keyframe, and past a copy of it on the frame immediately before its current frame, so you have two copies in a row, you will get the movement you are after. So if your keyframes are on frames 0, 10, and 20, for example, copy the keyfrmae on frame 10, and paste the copy onto frame 9, so you have the same keyframe twice, on frames 9 and 10.
    EDIT: it appears that the interpolation options control temporal interpolation (the timing of the keyframes), rather than spacial interpolation (the position of the path), and spacial interpolation is always smooth at present. This is something that we indend to rectify in the future, but for now, the duplicate keyframe technique I described above is your best option.
  • DannyDev
    DannyDev Staff Posts: 337 Staff
    edited September 2011
    You are correct Axel - the interpolation options in the timeline influence the interpolation over time and the behavior you are seeing is correct.
    Points are a special case because if you simply interpolate between the positions, you'll end up with jerky movement regardless of the changes to the individual components over time (think of a car turning suddenly on a pin as it rounds a corner). So in this case the software uses cubic bezier curves to smooth out the change.
    Your duplicate keyframe method effectively limits this spatial interpolation to the single frame between the two keyframes.
  • Thanks for that guys, the extra keyframe sorts it out for me.