2 Leg Character

Simple creation of a 2 legged character with basic FK/Ik switch possibility.

Step01 Prepared your model for rigging

Group all Geometry under one empty group call “mesh”. Also take the time to names others element of your scene. “optional for this tutorials”
Freeze Transformation and Delete History
Create a new Display Layers named “geometry” and add the current geometry selection into it. Mark this new layer as template.

Step02 Joint Creation

Create the joint for the leg and rename them.
- lf_upperLeg_jnt
- lf_lowerLeg_jnt
- lf_ankle_jnt
- lf_ball_jnt
- lf_toe_jnt
Create a single joint and name it
- Hips_jnt (Talk about C.O.G. position)
Move the “lf_upperLeg_jnt” to fit in the center of the “lf_leg_geoUsing the mirror Joint tools
Using the proper setting. Mirror across “lf_leg_geo”. Choose the proper axis.
Take this time to rename the prefix to the right side.

Step 03 IK Handle creation and basic foot roll setup.

Create 3 IK Handle
- 1 Rp solver from “lf_upperLeg_jnt” to “lf_ankle_jnt”
- 1 Sc solver from “lf_ankle_jnt” to “lf_ball_jnt”
- 1 Sc solver from “lf_ball_jnt” to “lf_toe_jnt”
Rename each of them like this. Matching the naming convention for the “_jnt”.
- lf_ankle_ik
- lf_ball_ik
- lf_toe_ik
Select the desired object. Group them, rename them and replace the center pivot of this new group to a new position

4. Create a NURBS/curve and shape it as desired

Rename it “lf_foot_ctrl”
Snap in translation this object to the “lf_ankle_jnt”
Freeze Transformation and Delete History
Parent “lf_backPivot_grp” to “lf_foot_ctrl”

Step 04 Creating behaviors for our foot setup.

Create new attributes to control the foot

//current selection

$SEL = `ls -sl`;

//add new float attribute call "EXAMPLE" on the current selection "$SEL"

addAttr -ln "EXAMPLE"-keyable true -at double -min -10 -max 10 -dv 0 $SEL;

//add new Boolean attribute call "EXAMPLE_Bool" on the current selection "$SEL"

addAttr -ln "EXAMPLE_Bool"  -at bool  $SEL;

setAttr -e-keyable true ($SEL[0] + ".EXAMPLE_Bool");

2. Create SDK to control the foot behaviors

Select appropriates object and attributes into the appropriate section of the SetDrivenKey windows.
Set the value of object and set key in the SDK windows “don’t forget to select each and every object and attribute

FootRoll

Pose01

lf_foot_ctrl.footRoll = 0

lf_backPivot_grp.rotateX = 0
lf_frontPivot_grp.rotateX = 0
lf_footRoll_grp.rotateX = 0

Pose02

lf_foot_ctrl.footRoll = 8

lf_backPivot_grp.rotateX = 0
lf_frontPivot_grp.rotateX = 0
lf_footRoll_grp.rotateX = 37

Pose03

lf_foot_ctrl.footRoll = 10

lf_backPivot_grp.rotateX = 0
lf_frontPivot_grp.rotateX = 67
lf_footRoll_grp.rotateX = 0

Pose04

lf_foot_ctrl.footRoll = -10

lf_backPivot_grp.rotateX = -50
lf_frontPivot_grp.rotateX = 0
lf_footRoll_grp.rotateX = 0

FootRock

Pose01

lf_foot_ctrl.footRock = 0

lf_anklert_rtSide_grp.rotateZ = 0
lf_anklert_lfSide_grp.rotateZ = 0

Pose02

lf_foot_ctrl.footRock = 10

lf_anklert_rtSide_grp.rotateZ = 65
lf_anklert_lfSide_grp.rotateZ = 0

Pose03

lf_foot_ctrl.footRock = -10

lf_anklert_rtSide_grp.rotateZ = 0
lf_anklert_lfSide_grp.rotateZ = -65

ToeTap

Pose01

lf_foot_ctrl.toeTap = 0

lf_toeTap_grp.rotateX = 0

Pose02

lf_foot_ctrl.toeTap = 10

lf_toeTap_grp.rotateX = -80

Pose03

lf_foot_ctrl.toeTap = -10

lf_toeTap_grp.rotateX = 80

BallTwist

Pose01

lf_foot_ctrl.ballTwist = 0

lf_ballTwist_grp.rotateY = 0

Pose02

lf_foot_ctrl.ballTwist = 10

lf_ballTwist_grp.rotateY = -90

Pose03

lf_foot_ctrl.ballTwist = -10

lf_ballTwist_grp.rotateY = 90

Knee

Using the connection editor create a “= relation” between concordant attributes go through unassigned attributes
Select “lf_ankle_ik” and click reload right
Select “lf_foot_ctrl” and click reload Left
Connect “knee” attributes with the “twist”

ikOffOn

Using the connection editor create a “= relation” between concordant attributes go through unassigned attributes
Select “lf_foot_ctrl” and reload Left
Select “lf_ankle_ik“, lf_ball_ik, lf_toe_ik and reload right
Connect “ikOffON” attributes with the “ikBlend” of each one of the selected ik_handle. X 3

fk_vis

Select “lf_foot_ctrl” and reload Left
Select “lf_upperLeg_jnt” and reload right
Connect “fk_vis” attributes to control the “visibility” of “lf_upperLeg_jnt“.

Remember the chart above if more a guideline, more then absolute references. Base on your joint placement and character you will get different value on the rotation.

Repeat Step 03 04 to complete the right leg

Step 05 Finalizing the rig Wrap up everything

1. From the top view using the EP Curve tools draw a linear arrow call “master”.

Freeze Transformation and Delete History
Create 4 empty group and call them (“skeleton”, “ctrl”, “pose”and “characterName” )
Parent “skeleton” and “ctrl” under “pose”
Parent “pose” under “master”
Parent “mesh” and “master” under “characterName”

2. Create a nurbs circle and rename it “cog_ctrl”

Position the “cog_ctrl” to the “hip_jnt” position.
Freeze Transformation and Delete History
Create a Parent and a scale constrain between “hips_jnt” “cog_ctrl”
Parent “lf_upperLeg_jnt” and “rt_upperLeg_jnt” to the “hips_jnt”
Parent “hips_jnt” to “skeleton”
Parent “cog_ctrl”, “lf_ foot_ctrl” and “rt_foot_ctrl” into “ctrl”
Select “hips_jnt” and change his Draw Style from Bone to None.

Step 06 Association of mesh with the rig

They will have 3 different ways for you to associate the character geometry to the rig. Each of them will have there pro and cons. But in this case due of the simplicity on the character you can use the one you wish.

Parent the geometry to the closest joint in the hierarchy
ParentConstrain and scaleConstraint the geometry to the closest joint in the hierarchy
Use efficient grouping to make it easier.
Use smoothBind and distribute the weight to the closest joint

Step 07 The final wrap up. Restrain the access to unnecessary attributes and object.

Lock and set the Ik Visibility to 0 for all of theme.

Create layer for rig. Add all “_ctrl” and skeleton object to it…
Lock and hide “foot_ctrl” scaling and visibility
~~“Hip_jnt” set draw style to none.~~
Lock and Hide every attributes on “characterName”
Be sure your SDK are similar on both side of the Body… Unless the character have a physical handicap ……

Notes about this animation Rig

To animate the IK FK switching for this rig. You must activate the Enable IK/FK Control inside Maya/ Rigging / skeleton menu.
This Rig is now ready for animation. The use of references model are really appreciated during production time. The usage of reference “model” with a string name as attributes will be the best way you you to create a reference in your scene.

Step 08 Changing the way the ankle affect the knee. “OPTIONAL”

This technique is also call Knee PV no flip

You may have observe that when you rotate the “foot_ctrl” you are also automatically moving the knee position. In some case that will be a PERFECT behavior. But some time you may want to get move freedom and not affecting the knee position when you are rotating the “foot_ctrl”.

Breaking previous work and creating new node for the new setup.
- Disconnect the twist attributes we did for the lf_ankle_ik.twist attributes
Create the Knee control
- Create a nurbs circle call lf_kneePV_ctrl.
- Place lf_kneePV_ctrl on the knee position. Freeze Transformation……
- Now move lf_kneePV_ctrl
  - For Character left knee. Move 5000000 units on the left side of the knee position.
  - For Character right knee. Move -5000000 units on the right side of the knee position.
Create a poleVectorConstrain so the lf_kneePV_ctrl will manipulation the lf_ankle_ik.
A twist effect should appear as the PV now pointing on the side of the character. Simply set the lf_ankle_ik.twist attributes as below.
- lf_ankle_ik.twist attribute to 90
- rt_ankle_ik.twist attribute to -90
Group twice the lf_kneePV_ctrl on himself
- Rename to lf_kneePV_ctrl_grp
- Rename to lf_kneePV_ctrl_grpCons
- Replace both pivot to lf_ankle_jnt.
Create two new attributes on lf_foot_ctrl
- kneeFollow_onOff, float, min0, max1, default1
- knee, float,
parentConstrain the lf_foot_ctrl to control lf_kneePV_ctrl_grpCons.
- Keyframe the Translation and rotation of lf_kneePV_ctrl_grpCons.
- Using the Connection Editor. Connect lf_foot_ctrl.kneeFollow_onOff to lf_kneePV_ctrl_grpCons.blendParent1
- Using the Connection Editor. Connect lf_foot_ctrl.knee to lf_kneePV_ctrl_grp.rotateY
Simply select the lf_legPV_cons set his visibility to 0, and lock the channel.
Parent lf_kneePV_ctrl_grpCons to a ctrl grp

Repeat Step 08part01 and 08part02 to complete the right leg

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