IK spline handle tool not working

[rafeiND2QG]

Hello forums, I have a pre-existing curve and am trying to rig some joints to follow the curve. Unfortunately though when I try to use the IK Spline Handle Tool, the IK spline that is created does not function as intended. I have attached a video to further explain what I mean. 

Help is appreciated, thank you. 

[Kahylan · Accepted solution]

Hi!

The reason why your rig works differently than his is not with the IK spline handle but with the way that he creates the curve. He uses a circle and then uses a Lattice deformer to stretch it out, this means that when he rotates the curve maya rotates a perfect circle and everything stays in place since the deformation of the lattice is applied after the transform calculations. Your curve on the other hand is a static oval, so when you rotate it it rotates out of place. All you need to do is recreate your curve using circle and a lattice deformer to shape it this time and it should work fine.

I hope it helps!

[rafeiND2QG]

That worked thank you!! Would you also happen to know why if I move the original NURBs curve away from the world origin, even if I freeze the translations, the lattice tool stops functioning as intended. I left the curve at the world origin but now I'd like to move it and still be able to apply a lattice deform. 

[Kahylan]

Yes, the lattice tool only works when the object it deforms is within the cage. So to move the curve around it is best to group the curve, the lattice and the lattice base together and move them as a group.

I hope it helps!