Hey, first post for the sake of solving this. I’ve been stuck on this one problem for ages and I still can’t find a suitable solution. A fair bit of text ahead, so you can just click on the images if you want a quick version. You should still spot the problem.
So I’ve got this robot arm (imagine Bender’s arm from Futurama) that I wanna rig. I want to be able to bend it in any direction comfortably and easily (and this includes backwards). Here’s the arm. The question is: How would you rig this?
My first thought was to create a thorough joint chain, and attach that to an EP curve (2 Curve Degree - and I connected it with an IK spline handle). Once I did this, I’d turn the EP’s into locators, giving me great control over the curve, and as a result, the joint and arm. Arm Rigged and the Curve.
This works fantastic (especially when I can offset the joints, so they retreat into the body). But there’s one huge problem. Whenever I move the entire character and rig forward, the curve behaves weirdly. Here are images of the Arm Problem, and one just showing What the curve is doing.
I suspect it’s doing that due to the relative position of the curve’s origin point. And that’s a big problem. I don’t want it to do that, since it completely messes up the arms when I try to move the character forward (it’s even worse when it rotates). It also happens only when I move the locators. If I move the EP’s themselves (also assuming I never converted them to locators), then the only problem is when I rotate the points. Here’s what happens when you rotate the EP’s, if you’re interested
The reason I’m not just using a basic arm rig is because it doesn’t let me offset the arm into the body, and I get a bad ‘slanting’ on the arm, like this.. Plus I’m finding it difficult to skin it well. Getting a smooth curve across the arm is difficult (the image is the best I could do), and I don’t want an obvious elbow (and I also don’t want the root of the arm to move at all).
How would one rig/skin something like this? I haven’t been able to find anything useful on the internet for a while. If you’ve found a tutorial on something like this, please let me know. The closest I could find was this tutorial on Bender, but it doesn’t allow for backward-arm bending.