Animating a Snake in 3ds Max - Spline IK

sinchross

Hi,

I'm using a IK Spline system and trying to animate a snake in the 3ds Max. The snake will need to coil and rotate around itself but the IK Spline Twist is making it twist when it is in a determined angle, I try everything to stop this behavior but don't have success...

Do someone to know a way to deal with it?

Thanks!

Hito

try looking up the tank track setup on youtube; it's a combination of spline IK and path constraint. I'm pretty sure there's something in there that keeps every link stay oriented in the correct direction

monster

If you search CG Society you'll find a bug from ~2005 where they explain a bug in Spline IK.
It's still around.

The workaround is

1. Create a duplicate dummy bone chain.
2. Apply Spline IK to the duplicate.
3. Position constrain your orginal bone chain to each duplicate.
4. LookAt constrain each orginal bone to the child of the corresponding duplicate bone. (You'll need to make an extra one at the tip of the duplicate.)
5. For each LookAt constrain, set the Upnode to a new target object, and set it to LookAt not Axis Align.

Now you can twist all you like and the move the target object to twist the bone chain.