Bone Priorities

When you're playing Oblivion, your character is almost always playing more than one animation at a time. Even doing something as simple as exploring a cave with a torch requires at least two animations: a walking animation and a torch-holding animation. The engine uses bone priorities to determine how to blend two or more animations. When transform data is being applied to a bone from more than one animation and these animations are playing at the same time the animation that assigns the highest bone priority to the transformed bone 'wins' and moves the bone in line with that animation. It is this blending which makes it possible for your character to run and attack at the same time, or to hold a torch and cast a spell.

When creating your own animations, therefore, it is important that you take into consideration other animations and how they will interact with your own. If you set your bone priorities too high, they may interfere with another animation which should, logically, take precedence. And if you set them too low, they may not appear to be working because they are being continually overridden by other animations. In general, moving animations should place higher priorities on the leg bones, and lower priorities on the arm and head bones, and attacking animations using the arms and hands should be weighted in the opposite direction. It pays to spend some time testing your animation in-game to see how it works in a variety of actions to get it looking good and playing nice no matter what the player is doing.

How to Find a Bone Priority in an Animation File

NifSkope: To find the bone priority in an animation (.kf) file, open the file in NifSkope and select (left-click) the 0 NiControllerSequence in the Block List window. In the Block Details window, find the Controlled Blocks entry and expand it. Each bone will have its own Controlled Blocks entry (the name of the bone is listed in the Value column). Expand the bone's Controlled Blocks entry and find the Priority listing. The bone priority appears in the Value column.

Blender: In the Buttons panel, switch to Object (F7) or Editing (F9) and look in the Constraints tab. Beneath the name of the selected bone you should see a box that displays the bone priority.

How to Assign Bone Priorities

NifSkope: To assign bone priorities in NifSkope, open the animation (.kf) file and select (left-click) the 0 NiControllerSequence in the Block List window. In the Block Details window, find the Controlled Blocks entry and expand it. Find the entry for the bone you wish to edit and double-click the value beside Priority.

Blender: To assign bone priorities in Blender, open a scripts window and select Scripts -> Object -> Set Bone Priority. This will set the priority for any bones you have selected in Pose mode.

You can also set the priority for a selected bone in the Constraints tab in the Buttons panel in either Object (F7) or Editing (F9) mode. Select the number after 'Priority:' and change it. See the sample bone priority data below to get an idea about what you should set it to.

Additional Notes

Bone Groups

The default _male armature can be roughly divided into two major bone groups: bones above the waist and bones below the waist. Within these groups it is possible to identify rough sub-groups: all bones in the chain beginning with the left clavicle (shoulder bone) descending to the left finger tip bones, including the upper arm and forearm twist bones and the Torch/Shield bone, appear to share the same bone priorities; a similar sub-group exists for the bones from the right clavicle to the right finger tip bones that includes the Weapon bone in place of the Torch/Shield bone. Both sets of leg bones, the tail bones, and the pelvis (along with the Bip01, Bip01 NonAccum, and SideWeapon bones) may be considered a sub-group as well, as they seem to share the same priorities, although in this case the sub-group is functionally the same as the group of 'bones below the waist'. The remaining bones display some variety: the head/neck/spine chain is often broken up with varying priorities based on the animation. The Quiver and BackWeapon bones, of course, are usually grouped with the spine bones.

Animation Groups

Idle animations have the lowest priority (about 20), which is appropriate since the player is not directly controlling the avatar during idles. Movement animations have higher (30) priorities, which allow the movement animations to override the idle animations when the player moves the avatar. Animations involving the casting of spells or melee attacks tend to set higher bone priorities for bones above the waist and lower priorities for bones below the waist. This allows the bones directly involved in the action to override movement or idle animations on the spine, head, and arms while still allowing the player to move the avatar with the higher priorities on the legs. Special bones, like the weapon and magic node bones are roughly grouped by location with the rigged bones. The Torch, Weapon, BackWeapon, Quiver, Bow, and magicNode bones are grouped with the bones above the waist and the Bip01, Bip01 NonAccum, and SideWeapon with the bones below the waist.

Stagger animations have very high bone priorities (70+), although they are occasionally exceeded by other animations. This, of course, makes sense since the purpose of the stagger is to 'override' the player's choice of actions and hence penalize them.

Bows and Spells

Bow and spell casting animations require certain bones that are only present in animations that execute bow and spell-related actions. Bow:0 (two bones), ArrowBone, and ArrowHelper01 in bow animations and magicNode in spell casting animations. Dashes in the chart for other animations indicate that no priority was set for the bone in the animation, indicating it was either not present or explicitly left blank. (I still have to check this.)

Sample Bone Priority Data

Bone Priorities for Default _Male 3rd Person Animations

Animation	AnimGroup	Cycle Type	Bip01	Bip01 Pelvis	Bip01 Spine	Bip01 Spine1	Bip01 Spine2	Bip01 Neck	Bip01 Neck1	Bip01 Head	Bip01 L Clavicle	Bip01 L UpperArm	Bip01 L Forearm	Bip01 L Hand	Bip01 L Finger0	Bip01 L Finger01	Bip01 L Finger02	Bip01 L Finger1	Bip01 L Finger11	Bip01 L Finger12	Bip01 L Finger2	Bip01 L Finger21	Bip01 L Finger22	Bip01 L Finger3	Bip01 L Finger31	Bip01 L Finger32	Bip01 L Finger4	Bip01 L Finger41	Bip01 L Finger42	Torch	ArrowBone	Bip01 L ForearmTwist	Bip01 L UpperArmTwist	Bip01 R Clavicle	Bip01 R UpperArm	Bip01 R Forearm	Bip01 R Hand	Bip01 R Finger0	Bip01 R Finger01	Bip01 R Finger02	Bip01 R Finger1	Bip01 R Finger11	Bip01 R Finger12	Bip01 R Finger2	Bip01 R Finger21	Bip01 R Finger22	Bip01 R Finger3	Bip01 R Finger31	Bip01 R Finger32	Bip01 R Finger4	Bip01 R Finger41	Bip01 R Finger42	ArrowHelper01	Weapon	Bip01 R ForearmTwist	Bip01 R UpperArmTwist	BackWeapon	Bow:0	Bow:0	Quiver	magicNode	Bip01 L Thigh	Bip01 L Calf	Bip01 L Foot	Bip01 L Toe0	Bip01 R Thigh	Bip01 R Calf	Bip01 R Foot	Bip01 R Toe0	SideWeapon	Bip01 TailRoot	Bip01 Tail01	Bip01 Tail02	Bip01 Tail03	Bip01 Tail04	Bip01 Tail05	Bip01 Tail06	Bip01 Tail07	Bip01 Tail08	Bip01 NonAccum
blockattack	BlockAttack	Clamp	27	27	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	-	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	-	75	75	75	75	-	-	75	-	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27
bowattack	AttackBow	Clamp	25	25	55	55	55	55	55	95	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25
castself	CastSelf	Clamp	26	26	46	46	46	46	46	96	66	66	66	66	66	66	66	66	66	66	66	66	66	66	66	66	66	66	66	66	-	66	66	46	46	46	46	46	46	46	46	46	46	46	46	46	46	46	46	46	46	46	-	46	46	46	46	-	-	46	66	26	26	26	26	26	26	26	26	26	26	26	26	26	26	26	26	26	26	26
handtohandattackleft	AttackLeft	Clamp	25	25	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	-	-	55	-	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25
handtohandattackleftpower	AttackLeftPower	Clamp	55	55	55	55	55	55	55	55	65	65	65	65	65	65	65	65	65	65	65	65	65	65	65	65	65	65	65	65	-	65	65	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	-	-	55	-	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55
handtohandblockhit	BlockHit	Clamp	27	27	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	-	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	75	-	75	75	75	75	-	-	75	-	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27	27
handtohandequip	Equip	Clamp	25	25	55	55	55	55	55	55	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	-	35	35	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	-	-	55	-	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25
handtohandrecoil	Recoil	Clamp	25	25	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	-	-	55	-	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25
handtohandstagger	Stagger	Clamp	70	70	70	70	70	70	90	90	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	-	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	-	70	70	70	70	-	-	70	-	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70	70
handtohandunequip	Unequip	Clamp	25	25	55	55	55	55	55	55	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	35	-	35	35	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	55	-	55	55	55	55	-	-	55	-	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25	25
idle	Idle	Loop	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	-	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	-	20	20	20	20	20	20	20	-	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20
jumpstart	JumpStart	Clamp	30	30	30	30	30	30	30	30	30	30	30	30	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	-	30	30	30	30	30	30	20	20	20	20	20	20	20	20	20	20	20	20	20	20	20	-	20	30	30	30	-	-	30	-	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30
walkforward	Forward	Loop	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	-	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	-	30	30	30	30	-	-	30	-	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30	30

Last updated July 20, 2011

© 2009-2011 Dave Finch

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