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How to have bones follow and loop around a spline?

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    How to have bones follow and loop around a spline?

    So I have this game project that I'm working on with an ATV and I'm trying to figure out how to rig the treads so I can have them move and react the way they would in real life in UE4 and have it be dynamic through the bones. (Video link below)

    I have the treads rigged, but I'm not too sure how to implement something like this into UE. Would it be possible to have the bones follow a curve to have the tread spin around it?

    Maybe with an animation blueprint or something like that?

    I've also tried to make a spline for it with one piece of the tread and make the tread that way, but I wasn't sure how to get them to spin around the spline. But with that method, I'm not sure if I'll be able to get the tread to bounce. But the most important thing is to get them to move.

    Is there a reason you can't animate it outside of UE4 and then use the animation in-game?



      The main reason is that the process of getting the joints to follow a curve in the same shape as the tread isn't the simplest thing to do. It tends to break pretty badly. There was one time I got close, but I wasn't able to get it smooth. I set up blendshapes and had it animated that way, but it's not natural and I wouldn't be able to add physics at any point in the way that I want.


        Can you not do this with PHAT by having the bones simulate physics by chance?
        It may not be the "best" way, but you'd automatically get accurate slack based on the weight of each bone.

        Why not use Niagara for this?

        I think it's the perfect use case for it... and the caterpillar track can also be variable in length by adding/removing particles....


          You could attempt to do this in shaders and tessellation. You know how you can animate UVs and get a scrolling motion? If you do this, but include a displacement map for your tracks, I believe it could be good enough to allow your tracks to rotate around the base shape. If you then use a few joints to shape the tracks, I believe you would be able to sell the illusion of the tracks being bent by the surface underneath. A bonus with this is that you can squash/bend/stretch the tracks and the tracks should still animate properly, just like it would with any other UV-animation tricks.
          Programmer, Rigger, Animator - Demo Reel 2015 - My RnD / WIP thread -
          Worked on: Kitten'd - Guardians of Valor (Android, iOS)



            Yeah, I thought about tessellation, I just need to figure out how to implement that into my model..
            I'm still learning UE so there's still a lot that I'm not too sure on how to do. But thank you guys for the ideas. I'll see if I can put them to good use.