IKHandle
07-24-2024, 07:43 PM
Here a little guide about ikhandle that I hope should help everyone.
IKHandle work with chain of 3 joint.(bone and joint is the same thing)
The first one will be the parent of second.
The second will be the child of the first, and the parent of the third.
The third will be the child of the second.
Exemple: shoulder --> elbow --> forearm
The first joint must have a joint as parent too. ( = you cannot use the armature master joint)
The chain will not move the third joint...so it do not neccessary require weigthing (noticed the _jointEnd with no weigth on the default game armature?)
You cannot have joint sharing the same position in a ik chain:
If two bone of a ik chain overlap (so second and/or third joint end up with a null (0, 0, 0) translation because it share the same translation as his parent) the mesh will be bugged:
To see in blender what your ikhandle should look like:
In pose mode, select the second bone of your ik chain and add an bone constaint:Inverse kinematic.
Then set the chain lenght value to 2.
If you followed the previous rules, writing your ikhandle bloc script should be easy.
Example:
Notice that I commented the parameter related to the pole vector.
TIKHandle.StartJoint
First joint of the ik chain (TJoint)
TIKHandle.EndEffector
Each handle is connected to effector node.
TNode.SNode
Each tnode is connected to a snode
TNode.Parent (TIKHandle)
The parent of the TIKHandle should be the "locator/track/target..." that will control the chain.
In short, it's the "target vector" of your ik.
TIKEffector.TranslationLink
Third joint of the ik chain.
TNode.Parent (TIKEffector)
Second joint of your ik chain.
SSimpleTransform.Translation (SIKEffector)
Must use the same value than the one used by the joint linked to the TIKEffector.TranslationLink parameter. (check the sjoint of it)
If the sjoint do not contain any...
this mean that the translation = (0, 0, 0) and that your didn't follow the rule!
SSimpleTransform. (SIKHandle)
Your SIKHandle should use the same parameter (rotation, translation, pivot, etc.) as the one used by the transform node connected to the TNode.Parent (TIKHandle) node.
If it do not contain any, it's mean that your SIKHandle only need a Object.Name parameter.
SIKHandle.PoleVector
Allow to ajust the pole vector (only if you didn't use a PoleVectorConstraint)
For the pole vector, you have two possible choice:
1. You use a PoleVectorConstraint, what mean that you will use a second locator as your pole.
2. You do not use a PoleVectorConstraint, what mean that you will use the rotation of your "target vector" as pole.
The target of your PoleVectorConstraint must be a ttransform
If the target of your PoleVectorConstraint is a ttransform from the anim bs file (and I'm pretty sure it will)...
It will be bugged!
To use a joint as target and/or fix the bug, you simply need to create a new T/S transform node that will use the given as parent.
Then link this newly created node as the target of your constraint.
Example: (I wanted to use the dit_freetool_group locator, but since it is already part of the anim file)
PE track label
Upper Body
Hand Left
Hand Right
Foot Left
Foot Right
Knee Left
Knee Right
Vertebra 1
Vertebra 2
Vertebra 3
Vertebra 4
Vertebra 5
Vertebra 6
Free Toy
TTransform Object.Name
body_up_target01
hand_L_target01
hand_R_target01
foot_L_target01
foot_R_target01
knee_L_locator
knee_R_locator
spine_clusterHandle03
spine_clusterHandle04
spine_clusterHandle05
spine_clusterHandle06
spine_clusterHandle07
spine_clusterHandle08
edit_freetool_group
Note that after adding a ikhandle, some of your joint may flip.
Pole are made to correct this flip.
Sometime, you will need to go correct the SJoint.JointOrientation Vector3f( X, Y, Z ); since the pole while correcting a flipping bone will flip a another one!
Its is possible that your joint may bend on the wrong side. (for exemple, a knee bending backward instead of forward)
This situation will occur if...
A) On your armature, the "knee" is straight.
There, the game cannot know in what direction the knee is supposed to bend.
To prevent this, people add a slight bend ( take a look at the leg and arm of the model include with collatkane)
B) On your armature, the leg bend on the wrong side.
Of course, you can fix thing by adding the SJoint.PreferredAngle Vector3f( X, Y, Z ); parameter to the faulty node.
Also, it is possible that for some reason, the "axis oder" of your bone get fucked up. (and it will prevent you ik chain to work correctly)
Mainly caused by armature not having correctly made.
I have no idea what we can do to fix this.
On a final note, there is an another kind of ikhandle, being know as IKSplineHandle.
Intended to be used with long curvy object like spine, tail, neck, etc.
But I did not figure out it usage.
So I had to use regular ik on my project where spline ik should have been more appropriate.
IKHandle work with chain of 3 joint.(bone and joint is the same thing)
The first one will be the parent of second.
The second will be the child of the first, and the parent of the third.
The third will be the child of the second.
Exemple: shoulder --> elbow --> forearm
The first joint must have a joint as parent too. ( = you cannot use the armature master joint)
The chain will not move the third joint...so it do not neccessary require weigthing (noticed the _jointEnd with no weigth on the default game armature?)
You cannot have joint sharing the same position in a ik chain:
If two bone of a ik chain overlap (so second and/or third joint end up with a null (0, 0, 0) translation because it share the same translation as his parent) the mesh will be bugged:
To see in blender what your ikhandle should look like:
In pose mode, select the second bone of your ik chain and add an bone constaint:Inverse kinematic.
Then set the chain lenght value to 2.
If you followed the previous rules, writing your ikhandle bloc script should be easy.
Example:
Code:
TIKHandle :local_K4N3_ikHandle . {[/color]
[color=#000000]TIKHandle.StartJoint TJoint :local_shoulder_NODE155;[/color]
[color=#000000]TIKHandle.EndEffector TIKEffector :local_K4N3_effector;[/color]
[color=#000000]TNode.SNode SIKHandle :local_SK4N3_ikHandle;[/color]
[color=#000000]TNode.Parent TTransform :local_edit_freetool_group_NODE179;[/color]
[color=#000000]// TBaseTransform.ConstraintArray [ PoleVectorConstraint :local_K4N3_ikHandle_poleVectorConstraint ];[/color]
[color=#000000]Object.Name "K4N3_ikHandle";[/color]
[color=#000000]};[/color]
[color=#000000]/*[/color]
[color=#000000]PoleVectorConstraint :local_K4N3_ikHandle_poleVectorConstraint . {[/color]
[color=#000000]Constraint.TargetArray [ TTransform :local_elbow_locator_copy ];[/color]
[color=#000000]Constraint.WeightArray Array_F32 [ 1];[/color]
[color=#000000]Object.Name "K4N3_ikHandle_poleVectorConstraint";[/color]
[color=#000000]};[/color]
[color=#000000]*/[/color]
[color=#000000]TIKEffector :local_K4N3_effector . {[/color]
[color=#000000]TIKEffector.TranslationLink TJoint :local_forearm_NODE157;[/color]
[color=#000000]TNode.SNode SIKEffector :local_SK4N3_effector;[/color]
[color=#000000]TNode.Parent TJoint :local_elbow_NODE156;[/color]
[color=#000000]Object.Name "K4N3_effector";[/color]
[color=#000000]};[/color]
[color=#000000]SIKEffector :local_SK4N3_effector . {[/color]
[color=#000000]SSimpleTransform.Translation Vector3f( 0, -0.03413, 0.01322 );[/color]
[color=#000000]Object.Name "SK4N3_effector";[/color]
[color=#000000]};[/color]
[color=#000000]SIKHandle :local_SK4N3_ikHandle . {[/color]
[color=#000000]// SIKHandle.PoleVector Vector3f( 0, 0.01236902177, 0.01571646519 );[/color]
[color=#000000]Object.Name "SK4N3_ikHandle";[/color]
[color=#000000]};Notice that I commented the parameter related to the pole vector.
TIKHandle.StartJoint
First joint of the ik chain (TJoint)
TIKHandle.EndEffector
Each handle is connected to effector node.
TNode.SNode
Each tnode is connected to a snode
[To see links please log-in or register here]
TNode.Parent (TIKHandle)
The parent of the TIKHandle should be the "locator/track/target..." that will control the chain.
In short, it's the "target vector" of your ik.
TIKEffector.TranslationLink
Third joint of the ik chain.
TNode.Parent (TIKEffector)
Second joint of your ik chain.
SSimpleTransform.Translation (SIKEffector)
Must use the same value than the one used by the joint linked to the TIKEffector.TranslationLink parameter. (check the sjoint of it)
If the sjoint do not contain any...
this mean that the translation = (0, 0, 0) and that your didn't follow the rule!
SSimpleTransform. (SIKHandle)
Your SIKHandle should use the same parameter (rotation, translation, pivot, etc.) as the one used by the transform node connected to the TNode.Parent (TIKHandle) node.
If it do not contain any, it's mean that your SIKHandle only need a Object.Name parameter.
SIKHandle.PoleVector
Allow to ajust the pole vector (only if you didn't use a PoleVectorConstraint)
For the pole vector, you have two possible choice:
1. You use a PoleVectorConstraint, what mean that you will use a second locator as your pole.
2. You do not use a PoleVectorConstraint, what mean that you will use the rotation of your "target vector" as pole.
The target of your PoleVectorConstraint must be a ttransform
If the target of your PoleVectorConstraint is a ttransform from the anim bs file (and I'm pretty sure it will)...
It will be bugged!
To use a joint as target and/or fix the bug, you simply need to create a new T/S transform node that will use the given as parent.
Then link this newly created node as the target of your constraint.
Example: (I wanted to use the dit_freetool_group locator, but since it is already part of the anim file)
Code:
TTransform :local_edit_freetool_group . {[/color]
[color=#000000]TNode.SNode STransform :local_Sedit_freetool_group;[/color]
[color=#000000]TNode.Parent TTransform :local_edit_freetool_rpc_group;[/color]
[color=#000000]Object.Name "edit_freetool_group";[/color]
[color=#000000]};[/color]
[color=#000000]TTransform :local_edit_freetool_group_copy . {[/color]
[color=#000000]TNode.SNode STransform :local_Sedit_freetool_group_copy;[/color]
[color=#000000]TNode.Parent TTransform :local_edit_freetool_group;[/color]
[color=#000000]Object.Name "edit_freetool_group_copy";[/color]
[color=#000000]};[/color]
[color=#000000]STransform :local_Sedit_freetool_group_copy Object.Name "Sedit_freetool_group_copy";[/color]
[color=#000000]STransform :local_Sedit_freetool_group Object.Name "Sedit_freetool_group";[/color]
[color=#000000]I created a bloc with many of the pe track locator (with the required parent tree) that you can copy paste in your scenes/.bs file.[/color]
[color=#000000]Some will require that you have the default armature tree with the root bone in your scene...[/color]
[color=#000000]and all will require that you have the TRS_group object.[/color]
[color=#000000]Of course, the _NODE number from thse two node may differ in your scenes/.bs file. (just ajust it)[/color]
[color=#000000]TTransform :local_parent_group . {[/color]
[color=#000000]TNode.SNode STransform :local_Sparent_group;[/color]
[color=#000000]TNode.Parent TTransform :local_TRS_group_NODE001;[/color]
[color=#000000]Object.Name "parent_group";[/color]
[color=#000000]};[/color]
[color=#000000]TTransform :local_parent . {[/color]
[color=#000000]// TBaseTransform.ReparentID I32(1000);[/color]
[color=#000000]TNode.SNode STransform :local_Sparent;[/color]
[color=#000000]TNode.Parent TTransform :local_parent_group;[/color]
[color=#000000]Object.Name "parent";[/color]
[color=#000000]};[/color]
[color=#000000]TTransform :local_foot_L_target01 . {[/color]
[color=#000000]TNode.SNode STransform :local_Sfoot_L_target01;[/color]
[color=#000000]TNode.Parent TTransform :local_parent;[/color]
[color=#000000]Object.Name "foot_L_target01";[/color]
[color=#000000]};PE track label
Upper Body
Hand Left
Hand Right
Foot Left
Foot Right
Knee Left
Knee Right
Vertebra 1
Vertebra 2
Vertebra 3
Vertebra 4
Vertebra 5
Vertebra 6
Free Toy
TTransform Object.Name
body_up_target01
hand_L_target01
hand_R_target01
foot_L_target01
foot_R_target01
knee_L_locator
knee_R_locator
spine_clusterHandle03
spine_clusterHandle04
spine_clusterHandle05
spine_clusterHandle06
spine_clusterHandle07
spine_clusterHandle08
edit_freetool_group
Note that after adding a ikhandle, some of your joint may flip.
Pole are made to correct this flip.
Sometime, you will need to go correct the SJoint.JointOrientation Vector3f( X, Y, Z ); since the pole while correcting a flipping bone will flip a another one!
Its is possible that your joint may bend on the wrong side. (for exemple, a knee bending backward instead of forward)
This situation will occur if...
A) On your armature, the "knee" is straight.
There, the game cannot know in what direction the knee is supposed to bend.
To prevent this, people add a slight bend ( take a look at the leg and arm of the model include with collatkane)
B) On your armature, the leg bend on the wrong side.
Of course, you can fix thing by adding the SJoint.PreferredAngle Vector3f( X, Y, Z ); parameter to the faulty node.
Also, it is possible that for some reason, the "axis oder" of your bone get fucked up. (and it will prevent you ik chain to work correctly)
Mainly caused by armature not having correctly made.
I have no idea what we can do to fix this.
On a final note, there is an another kind of ikhandle, being know as IKSplineHandle.
Intended to be used with long curvy object like spine, tail, neck, etc.
But I did not figure out it usage.
So I had to use regular ik on my project where spline ik should have been more appropriate.
[To see links please log-in or register here]