Vitruvian bones and IK?

[SimplSam]

How do people cope with Vitruvian bones and IK?

I have IK working as desired with a simple arm rig, but when I introduce the 2nd lower vitruvian limb bone it kills IK on the upper limb. This is normal / expected for normal bone structures, but I was hoping Vitruvian Bones would permit IK with multiple lower limbs due to the fact that only one limb bone is active at any time.

At the moment the solution might involve a bunch of reparenting. But keen to see if I missed a trick ...

[Greenlaw]

Hmm...can you share an example?

FWIW, FK with Vitruvian Bones works here. With the Manipulate Bones tool selected, I just hold Alt and use FK on any bone inside the V-Bones group as normal. Then Alt-C or -D to change V-Bones groups, and press Alt to use FK in this group. So far I haven't had a problem with that.

[Greenlaw]

Or did you mean IK? IK should work too but if you have another bone branching out from a bone, IK will terminate there.

So if you have parented another bone to the upper arm bone besides the lower arm bone, that could disable IK for the upper arm bone. To work around this, select the other bone and enable Ignored by Inverse Kinematics (in Constraints) for that bone. This should allow IK to be active on the upper arm bone. (In my rigs, I need to do this for a hidden the elbow bone.)

Hope this helps.

[SimplSam]

Ha. I have updated the subject to "IK" !!!

And the issue is where we have multiple Vitruvian limbs on the same upper bone.

So... "Ignored by Inverse Kinematics" works as you have indicated, but it is not keyframable/animatable. Therefore - I can only ever have one of the Vitruvian child limbs controlling the IK.

I have disabled Vitruvian below to show both bones, but "Arm lo 1", and "Arm lo 2" are in a Vitruvian group and each needs to be IK controlling "Arm up" - when they are active (respectively).

[synthsin75]

Quick edit to the IsEnabled function will automatically allow IK for only the active Vitruvian groups:

Code: Select all

function LM_BoneGroups:IsEnabled(moho)
	local skel = moho:Skeleton()
--syn\/
	--automatically enable IK for active Vitruvian group
	for i=0, skel:CountBones()-1 do
		if (skel:Bone(i):IsGroupVisible()) then
			skel:Bone(i).fIgnoredByIK = false
		else
			skel:Bone(i).fIgnoredByIK = true
		end
	end
--syn/\
	if (skel == nil) then
		if (self:ShouldUseParentSkeleton(moho)) then
			skel = moho:ParentSkeleton()
		end
		if (skel == nil) then
			return false
		end
	end
	if (skel:CountBones() < 1) then
		return false
	end
	return true
end

[Daxel]

I didn't notice this VB limitation. Greenlaw's explanation makes a lot of sense. And that fix from Wes was the fastest of the west. Even if this is the expected behaviour for a hidden bone, it is inconvenient with V bones. I hope they implement that improvement on the next version. I'm still hyped about VB's potential even if I have only used them once so far.

[SimplSam]

Wow! That was quick indeed.

Working like a charm!

Thanks all

[Greenlaw]

Hmm...I guess I hadn't noticed because I normally use FK when animating arms. But of course I do need IK for arms when I pin the hands to something (hips, table, etc.,) so this is good to know. Thanks for creating a patch Wes, and so quickly too! I'll give it a try tonight.

[lucasfranca]

Quick edit to the IsEnabled function will automatically allow IK for only the active Vitruvian groups:

Code: Select all

function LM_BoneGroups:IsEnabled(moho)
	local skel = moho:Skeleton()
--syn\/
	--automatically enable IK for active Vitruvian group
	for i=0, skel:CountBones()-1 do
		if (skel:Bone(i):IsGroupVisible()) then
			skel:Bone(i).fIgnoredByIK = false
		else
			skel:Bone(i).fIgnoredByIK = true
		end
	end
--syn/\
	if (skel == nil) then
		if (self:ShouldUseParentSkeleton(moho)) then
			skel = moho:ParentSkeleton()
		end
		if (skel == nil) then
			return false
		end
	end
	if (skel:CountBones() < 1) then
		return false
	end
	return true
end

Wow, really good! Does this work for common bone structure too?

[synthsin75]

Wow, really good! Does this work for common bone structure too?

With another quick edit, yes, it can work with any selected bone too:

Code: Select all

function LM_BoneGroups:IsEnabled(moho)
	local skel = moho:Skeleton()
--syn\/
	--automatically enable IK for any selected bone
	local sel = skel:SelectedBoneID()
	for i=0, skel:CountBones()-1 do
		if (skel:Bone(i).fSelected or skel:IsBoneChild(i, sel)) then
			skel:Bone(i).fIgnoredByIK = false
		else
			skel:Bone(i).fIgnoredByIK = true
		end
	end
--syn/\
	if (skel == nil) then
		if (self:ShouldUseParentSkeleton(moho)) then
			skel = moho:ParentSkeleton()
		end
		if (skel == nil) then
			return false
		end
	end
	if (skel:CountBones() < 1) then
		return false
	end
	return true
end

[lucasfranca]

Wow, really good! Does this work for common bone structure too?

With another quick edit, yes, it can work with any selected bone too:

Code: Select all

function LM_BoneGroups:IsEnabled(moho)
	local skel = moho:Skeleton()
--syn\/
	--automatically enable IK for any selected bone
	local sel = skel:SelectedBoneID()
	for i=0, skel:CountBones()-1 do
		if (skel:Bone(i).fSelected or skel:IsBoneChild(i, sel)) then
			skel:Bone(i).fIgnoredByIK = false
		else
			skel:Bone(i).fIgnoredByIK = true
		end
	end
--syn/\
	if (skel == nil) then
		if (self:ShouldUseParentSkeleton(moho)) then
			skel = moho:ParentSkeleton()
		end
		if (skel == nil) then
			return false
		end
	end
	if (skel:CountBones() < 1) then
		return false
	end
	return true
end

Forgive me for my ignorance, but where do I put this code? Would it be in .LUA file? If yes, which one? Or is it a Layer type script?

[synthsin75]

This replaces the IsEnabled function of the Vitruvian bone tool...which is called lm_bone_groups.lua.

I would suggest copying it, and its pngs, to your custom content folder and editing it there. Don't edit the stock scripts in the installation folder.