Follow path: object won’t ‘follow path’, object is positioned away from path(connected by line)

Support Animation and Rigging
#1

Object won’t follow path. For some strange reason, ‘follow path’ added after my ball bounce animation key frame affects the start of the ball bounce animation (the bounce animation is already ‘done’, next I want the ball to follow a certain path (such as rolling down a slope).

I’ve tried multiple tutorials, and the same issue continues to persist. All tutorials uses a ‘new file’ to create their ‘follow path’. I haven’t seen a tutorial where follow path is added after objects have already been animated.

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  1. Ball bounce animation
  2. Next I want the ball to eventually roll down a slope. The video itself just uses a straight line because I wanted to make sure the concept of adding ‘follow a path’ first works.
    https://www.youtube.com/watch?v=BL0Hsq7A19c

This is the easiest ‘follow path’ animation tutorial I’ve come across. And it works but only if I don’t already have something animated.

#2

Here’s what I’d do:

  1. Start with animated bouncing object Ball, in any arbitrary loc/rot/scale. Ball is animated in only one channel, up-and-down motion only. If necessary, advance to a frame where the ball is on the “ground”-- at its minimum world Z.

  2. Add empty. Move empty in global Z axis to the visual bottom of the ball. Parent Ball to Empty.

  3. Snap cursor to Empty. Add a curve object. Enter edit on the curve object and G X 1 enter (move it so the first control is at the origin of the curve. This just makes it so that your curve starts where your ball starts, and is maybe more habit for me than necessary.)

  4. Give Empty a follow path constraint targeting the curve object. You may notice a jump-- don’t worry yet.

  5. Select Empty and reset location (alt g). Now everything should be in the proper place.

  6. Optionally (how I’d prefer to animate it), set the follow path constraint to fixed position, set offset to 0 at frame 0 and keyframe, go to end of animation, set offset to 1.0 and keyframe.

  7. Edit the curve to be the curve you want.

bouncePath.blend (825.1 KB)

File has animation demonstrating what you get.

#3

Thanks Bandages… I can copy/paste your comment for reference and save time watching tutorials. You covered the details like the pro I know you are. Always great to hear your comments.

1 Like
#4

Thanks, I’m glad it’s useful! I do wish more tutorials got to the point; I wish there were more tutorials that were in text, where you can learn the process in minutes rather than hours. I’ve been thinking lately that maybe I should try to start updating the noob-to-pro wiki, which is woefully out of date when text+pics is such a better format for learning than video.

#5

Note: the blend file likely didn’t show up with animation because I’m still on blender version 2.79b. Latter versions simply didn’t work on my computer. 2.8x crashes ], and can’t open. Version 2.91 originally opened, but the preview playback (pressing space bar) had a 2 fps playback. By default, I looked for an older version, started on 2.65 and settled on 2.79b.

I’m going to try to give it another go on your instructions. right now because the first time, I was unsuccessful.

#6

Ok. None of that ought to be 2.91 specific, it’s all acted the same since 2.79.

#7

It worked … but … some issues … when introducing rotation and … object being stuck, can’t proceed past path point

Does anyone ever start their animation over from scratch if you can’t figure out how to fix a problem?

  1. It works … with rotation.
    https://www.youtube.com/watch?v=KS0GSJZynWY&feature=youtu.be

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  2. Object can’t proceed
    https://www.youtube.com/watch?v=RNfanbz0bCU&feature=youtu.be

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  3. Removing parent? What’s the proper way to remove the parent at the yellow arrow? Couldn’t exactly get Alt-P to work ‘right’.

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#8

I don’t think you should be using offsets that large. It may be different way back in that version (I have a vague memory of offset being a 0 to 100 or 0 to -100 value?) but I don’t think you should ever be using numbers that large.

You can’t remove parenting. Not in the middle of an animation. What you can do is extend the path to cover your complete animation, or use a child-of constraint instead of a parenting relationship, or copy transforms from a different object (empty) with different parentage, or swap out two different objects that look the same at a specific frame. With constraints, you can animate the constraint influence; you can use apply visual transform to “snap” to constrained positions on frames where you animate the influence to 0.

You should try this as a learning tool: select your empty, the ball’s parent. Ctrl a -> apply visual transform. It jumps, don’t worry. Now mute your follow path constraint and it jumps back. Exact same transformation, but from regular old transform values, not from your constraint. That’s what visual transform does.

#9

Note: I’m a beginner beginner.

I would rather not change the ‘offset’ value because it does not seem right to me (as a beginner) having to adjust the value so much, but unfortunately in tutorials that’s all they change to move the object along the path. Tried doing the transform thing and muting thing, but not sure I’m doing things correctly (videos below)

As far as removing the parent in the middle of the animation, where the ball sits at the end of the slope is, for example where I want to the ‘follow path’ animation to stop is what I’m thinking. And then I’ll finish animating the portion where the ball rolls off the ramp/slope by doing traditional key frames (beginner method) unless there’s a better way. Nit sure if this is the correct way to go about using ‘follow path.’

Your middle paragraphs instructions/suggestion is foreign to me and I would need to research how to do those things.