So DavidBrennan brought up a challenge: Making a train follow a path realistically.
I thought I would have a solution in minutes, through some combination of Follow Path, Parent > Follow Path, Clamp To, Track To, Limit Distance, Child Of, Empties, No Empties… etc.
Nope. After toying with it for some time I’ve decided to start a thread. Here is the most basic version, using two cars that have been [Ctrl+P] > "Follow Path"d to the Curve. It doesn’t work, of course, because both of them follow the shape of the path starting with their offset from it—so their relative angle and position on the path never changes.
Here is pretty much all I’ve figured out for sure:
Each link (whether that ends up being a chain of Empty’s or the actual train cars) needs to have some kind of “Follow Path” (wheter that be a Follow Path Constraint or a [Ctrl+p] > “Follow Path”). Otherwise the cars will not be at the right spots at the right times. No amount of chaining the back cars to the front cars will produce the track-following effect.
I think that’s the only part I’ve figured out, really.
Thanks a lot for these - although I haven’t tried them out yet, because I’ve been rendering for the past 14 hours or so. Once that’s done (sometime late tonight) I’ll make sure to check these out and write step-by-step instructions here in the thread.
One of the primary problems was taking the mesh with many vertices but only having it move at the couplings between the cars.
An Armature solves that problem pretty well (and it would probably look even more precise if my Vertex Groups were better and there were a few more Bones - but this was just a crude construction for demonstration purposes.)
So then, I thought that I could simply have those four Bones follow the train track Path - I’d used the Curve Modifier before - and thought that it would look nearly perfect: the Bones would snake along the Curve, but its child Object, the train, would only twist and warp at the joints between the Bones…
Note that the only way I could animate this was by the Curv’es “Path Animation”, which I don’t like as much as just being able to Keyframe the Object itself.
But if anybody knows how to get Bones to move along a Curve in the way needed in this situation, I would appreciate the info greatly. Attached is the .Blend, as well (stored via MediaFire because this site limits message Attachments to 3 per post):
Actually, I’m sorry to say, I haven’t even tried that yet - although I did see you update the post. I had spent a lot of time on the Bone technique before you had updated the post, and so, ya know, I was just emotionally invested in seeing it work.
Even though you have a solution, I would still like to know why the Bones can’t follow a Curve in this manner just because (a) I would like to understand it and (b) I do think that animating an Armature itself is easier than dealing with the Curve’s “Path Animation”. For me personally, I hate that thing and always prefer to keyframe an Object itself rather than the Curve.
