Spline IK with Effectors in World Space

Development Programming & Scripting
1

Hi, with regards to the Animation Blueprint, the Two Bone IK and FABRIK nodes have a way to switch the effector location space from component (or bone) to world space. However, the Spline IK node does not have this option - should I assume that the effector (control points) are in component space? Say my hip and my head transforms are given in World Space - how would I convert these into the right inputs for Spline IK?

How does performance of Spline IK compare to FABRIK? Is one more expensive than the other?

There seems to be a way to control the roll and twist of the spine, but what about in the pitch direction? Or does Spline IK only handle bending in one dimension?

2

Did you figure out how to fix this ? I’m also confused about this. Is SplineIK using component space or even bone space ?

3

am also interested in this. Spine IK in global space would be awesome. I am also a bit confused about how spline Ik works. Sometimes it seems to have some odd behavior like rotations.

4

It works in bone space… very UNCONVENIENT

5

Not true. It is component space and that is why this node does not work:
image

I wrote a simple node to convert world to comopnenet space:

void UVRIntimateHelperNodes::WorldLocationToComponentSpace(const USkeletalMeshComponent* skeletalMesh, const FVector& worldSpaceLocation, FVector& componentSpaceLocation)
{
	if (skeletalMesh == nullptr)
		return;

	const FMatrix componentInverseMatrix = skeletalMesh->GetComponentToWorld().ToInverseMatrixWithScale();
	componentSpaceLocation = componentInverseMatrix.TransformPosition(worldSpaceLocation);
}

I know it is an old thread by i didnt find a sufficiant answer anywere and quite some people requesting a solution. Hope it still helps someone.