Right-Click Select This is a read-only archive
← All ideas
  • Published 29 Oct 2017

Curve Tilt to Local Y rotation for Hooks and SplineIK

Curves are useful for many things, but their usefulness in rigging is limited by the lack of proper Local Y rotation.

The main places this matters is for Hooks and SplineIK constraint. Hooks can move and rotate curve control points, but cannot rotate them on Local Y, so cannot twist them. SplineIK'd bone chains also cannot get any roll from the curve they are attached to, even if you change the curve's tilt. However, meshes attached with the Curve modifier DO get twist from the curve's Tilt.

It would open up a lot of new rigging options if Hooks could affect the twist of control points, and if twist was translated to Local Y for bones attached with SplineIK.

100%

Development Status: Open

Upvote 9 Downvote 0
aversionofreality
29 Oct 2017

4 Comments

hadriscus

Absolutely yes. Right now we need to have a differently-weighted "copy rotation" constraint on every bone in the splineIK chain, which is a hassle to set up, whereas deriving the twist value from the curve tilt would be so much more straightforward.

As you said, two things would be necessary for this to work (just laying this out for clarity) :

  1. the hook modifier would need to actually affect the curve point's tilt, not just its position in space and handle orientations
  2. the splineIK constraint would need to take the tilt into account to twist the bone chain

Cheers, good idea, I've been missing this for a long time, and would love to see it in Blender.

Hadrien

2
Pentium

Really want that, had some headaches with figuring out how to rig a flat cable, wish more ppl talked about it, maybe it've gotten implemented already. Maybe it should be a check for modifiers so you can configure if you want to lock twist to controller or not.

Anyone have workaround good enough? Having a flat cable I can't really rig for animation because it keeps twisting in its connetion points.

pxy-gnomes

In Blender, another Spline Skinning method, besides the approach that is quite complicated with Spline IK Bone Constraint, is the approach with Bendy Bone Splines.

Bendy Bone Splines are not super-simple to work with, but at this point, there are good enough content out there covering mostly everything fundamental about them in Rigging. They do not suffer the Twist feature limitation because they do not rely on an external Curve Object. Although it's also Spline Skinning method, there exist even a method that actually 'converts' Bendy Bones to regular Deform Bones, making the latter suitable for conventional Linear Blend Skinning, usable for 3D Animation Baking and Exportation.

1
Pentium

Thanks, that helped, did knew about bendy bones but I guess I wasn't knowing full capabilites.

1