I’m trying out the spline IK constraint these days, it is AWESOME, but I’m running into some problems. First, I wonder how to control the twisting in my constrained bone chain. The spline points are hooked to a few control bones, the rotation of which don’t seem to affect the curve at all. I also tried driving the “tilt” property of the curve points with the control bone’s roll… no luck. I can use rotation constraints on the entirety of the bone chain, starting from the top and gradually decreasing in influence… but this is a chore, is there another way ?
Then : I tried using a nurbs curve, but to have it curve smoothly I apparently have to set a U Order of 3 (inside the curve properties), however that shortens the curve and the contrained bone chain along with it, which makes it unusable. So I’m using a bézier, which works fine so far - apart from the twisting issue. I was just wondering. If someone could light my bulb. Thank you !
The spline points are hooked to a few control bones, the rotation of which don’t seem to affect the curve at all. I also tried driving the “tilt” property of the curve points with the control bone’s roll… no luck.
Are saying that you are controlling your IK with a curve? need more explanation here, please some images or .blend
I’m using a spline IK constraint (see manual for explanation and set-up instructions). It is a technique commonly used when one needs a smooth deformation along a bone chain. Using a bézier curve in place of a NURBS curve also allows to manipulate the curve point’s handles, affecting the curve interpolation (just like f-curves in animation).
Joshua Leung (developer of the spline IK constraint) told me there was no roll for the IK spline, and none planned in the foreseeable future, too. So I guess I gotta do with the curved b-bones !
Hi, This message is from future and splineIK cannot be twisted. I would like to know how solved the strech problem. Right now everything seems to work but body stretched instead of moving alone the curve. Please help
Unfortunately it still can’t, but there are ways to work around that. You mention a ‘stretch problem’ - what is it exactly ? That doesn’t sound like the issue I was having (twisting). You can open a new thread with your question and a .blend file, and tag me so I’m notified.
Hi, Unfortunately I can’t share the file. may i will replicate the stuff on my pc and then will share it with you. But for now, I can share the link of my thread.
Here is my file. Everything seems to be working normally. I switched the y stretch to none and its working. Is it also needed to parent the curve to armature? SnakeSplineIK.blend (702.2 KB)
It depends on what you want to do with it. Typically, you’d either parent the curve to a bone in the armature, or give it a hook for all control points (as you did in the linked file.) They can have slightly different effects for other uses of the curve, but for a spline IK, they’re the same thing.
