Best Approach for Rigging tank threads/chainsaw chain/bike chain with Bones

I’ve been trying to find a way to rig a chain of Bones to follow a circular path but so far I haven’t had any luck on creating a proper rig. I would like to contain the solution within Bones and Constraints and as much as possible without Drivers. Any ideas? :confused:

Try a video search for rigging tank tracks, there is a- ahem tankload of them! :wink:

Its generally the same principle: a single link with a curve modifier follows a circular spline, has a controller that makes it travel around the spline, and gets repeated with an array modifier.

There may be a couple of variations with what comes after these steps, so you might have to look around to see what suits you. Fortunately, it looks like a popular topic.

Good Luck!

Thanks for the reply but I’ve searched a ton of them but none so far that I’ve seen that makes use of Bones only.

The main problem about the Curve Modifier is… it’s a Modifier and not a Constraint and has the problem of deforming the chain :no:. I’ve watched Chris Kuhn’s CG Cookie on rigging a tank to avoid deforming the parts with a Curve Modifier but it’s more of a ‘work around’:spin:.

And yes, i’m aware of the Rigid Body Simulation rig approach but I want to limit the solutions to Bones and Constraints only.

You might consider Nathan Vegdahl’s Humane Rigging tutorial series. He doesn’t have a lesson on tank treads specifically, but what he does do is give you every tool in the pouch and the knowledge you need to design your own from scratch. You can find the videos on YouTube, but this series is well worth the money. And when you buy it, you also get all the extras (.blend files, etc.) to go along with Nathan’s excellent explanation of just how rigging works.

This isn’t, however, a shortcut to getting your tank treads done. You’ll have to commit to the long haul to get the most out of it. Give yourself a few weeks, minimum, to absorb all this information. You won’t regret it, I promise.

There is distortion, but from what I’ve seen, its hardly noticeable if at all. Is this for a technical illustration, game or short film?

There is this video whose description talks about parenting the link to a plane, and then using the array/curve on the plane to avoid distortions. I might try that out later.

Yeah. Nathan’s Humane Rigging is what introduced me to Rigging and it’s an excellent watch (it actually DID took me time to absorb it).

I want to know if there’s at least someone who’s already done tank threads or with similar solutions by using Bones that’s willing to share their knowledge. Otherwise, i’ll have to ‘brute force’ finding a solution. So far the approaches I can think of is a convoluted mess.

Also, i’m more of a 3D modeler and less of a rigger so i’m having trouble trying to commit my time and energy for a solution:(.

As much as the Curve Modifier is the most practical within Blender personally if find it… really weird, though I have to thank the approaches and made me learn how to use Duplis and Vertex Parenting.

I just really want to know if it’s possible to achieve a technically “correct” rig by using bones for chains that follow a path, hopefully someone has achieved it:spin:.

For a project I want to apply it is that I plan to export a tank and chainsaw model with animation to Sketchfab and want to use Bones to drive the animation.

Yeah, I hear ya. So many of us are in this situation. It’s been a few years since I studied rigging with Nathan (via Humane series, of course, not in person) so I’m rusty.

But, if I come up with any ideas, I’ll let you know.

If you want to do a technically perfect rig you can, I have, done it with bones, track to constraints and follow path constraints. In fact this is how I rig railway vehicles so you can look on my Magnum Opus thread to see how. The maths is quite complex and the rig is hard to build, particularly if you are new to rigging. So ask yourself how much do you really want to do this? Are you ready for a long haul to do it? So read the relevant post from my train thread then let me know if you want to go ahead and I can help.

Cheers, Clock.

Seems like an interesting read. I’m already half expecting a complex solution so it doesn’t really bother me.

It’s been a while since I’ve posted this but I think I’ve found a simple solution incorporating bones without deformation. I’ve been working on a similar project where I need a snake rig specifically moving the bone chains with a controllable path.

It’s kinda annoying how this is almost never documented or shared. I plan on sharing this info soon once I finish the rig on a new thread so stay tuned if there are anyone interested.

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How true, so share what you come up with please!

A way to overcome the distortion of the track pads is this:

Create a plane object the size of one track pad/link.
Create the curve for the path of the track/chain
Add an Array Mod with “Fit Curve” as the number in the “Fit Type”.
Add a Curve Modifier with the curve as the target.
Move the plane in the Deformation Axis to animate.
Parent your real track pad to the plane object.
Set plane object “Duplication” to “Faces”

So, why does this work, Plane objects cannot be curved by a Curve Mod - they don’t have enough vertices they would have to have at least three down each deformation axis to bend. Duplication set to “Faces” repeats the track pad/link on every plane in the Array.

Cheers, Clock. :beers:

Images:


Flat Pads


Curved Track