Lesson 17 NURBS Rigging

Posted on Posted in AutoDesk Maya, Foundation 2008, Tutorials

Hierarchy

Organize the hierarchy and name all your nodes

  1. Open your scene.
    • – Open your scene from the last assignment.
  2. Rename Multiple Objects
    • Rename multiple files easily and simultaneously.
    • – Select all the objects that have similar names, such as the hair.
    • – In the top right corner of the application, set the rename option in the input field.
    • – Enter hair in the input field and press [ENTER].
    • Note: Every selected object will be assigned the unique name followed by a number. The order of selection defines the order of the attached number.
    • – Rename your nodes.
  3. Hierarchy
    • – Group every object in a folder called geo.
  4. Skeleton
    • – Select ANIMATION || Skeleton > Joint Tool.
    • – From the side view, draw a skeleton for the character as follows.
    • Note: Try to visualize how the joint pivot will affect the deforming geometry.
    • TIP: Use the arrows to navigate in the skeleton while creating the limbs.
    • – Switch views to move the leg joint to its proper location.
    • – Rename every joint, with a l or r prefix for the left and right of the body.
    • – Duplicate the toe joint chain to accommodate the third toe.
  5. Mirror the leg
    • – Leg joint Selected: ANIMATION || Skeleton > Mirror Joint >
      • Mirror Joint Options:
      • Mirror Across: YZ;
      • Mirror Function: Behavior;
      • Search For: l;
      • Replace with: r;
      • These options will change the left prefix to the right prefix.
      • – Click [MIRROR]
      • Note: Check the names of the new joint since some names might have been altered by the search and replace function.
  6. Place and Mirror the Eye Joint
    • The eye joint should be placed in the center of the eyeball since it is perfectly round. Align a joint to the center of a shape.
    • – Select the surface first which is the eyeball. Then SHIFT + SELECT the eye joint.
    • ANIMATION || Constrain > Point.
    • The eye joint will move to the pivot location of the surface.
    • – Delete the constraint. Select the Point Constraint from your Outliner or select the eye joint and press the down arrow.
    • – Delete the constraint node.
    • – Mirror the eye joint after you are done.
  7. Reorient all the Joints
    • You probably rotated or translated your joints. Reorient your joints to the joint’s local axis.
    • – Select MAIN || Modify > Freeze Transformations.
    • This removes all values for any joint or surface from the Channel Box.
    • ANIMATION || Skeleton > Orient Joint.
    • This  reorients the joint so each local rotation axis points at the first child.
    • – Display Local Rotation Axes: General || Display > Transform Display > Local Rotation Axes
    • Note: In the Outliner, make sure that joints with multiple children have a first child in line with the desired rotation axis. Ex: IF the pelvis’ FIRST child is one of the legs, the local rotation axis of the pelvis will be pointing at that leg. Since the pelvis’ FIRST child is the spine in the Outliner, the local rotation axis will be pointing at the spine.. X direction points towards childs.
  8. Set Preferred Angle
    • – RMB on the pelvis joint: Select Set Preferred Angle.
    • Doing so saves the current pose of your skeleton.
  9. Save
    • 052212_17-nurbsRigging_02.ma

 

 Skinning

Skin the body using Rigid Binding. Rigid binding assigns each surface point to a single influence point. This type of skinning could break dense geometry when bending, but because NURBS geometry tends to be smooth when bending when there are few CVs, rigid binding will do the trick.

  1. Skin the body
    • – Select the body surface, then SHIFT + SELECT the pelvis joint.
    • ANIMATION || Skin > Bind Skin > Rigid Bind > □

      • Rigid Bind Options:
      • Bind to: Complete Skeleton;
      • – Click [BIND SKIN]
      • *
    • – Test the affect of the joint rotation on the body geometry.
  2. Edit Membership Tool
    • You will notice that some points aren’t assigned to the proper joint when testing. Use the edit membership tool to rectify it.
    • – Select the body geometry.
    • – Select ANIMATION || Edit Deformers > Edit Membership Tool.
    • – Click on the pelvis joint to highlight it.
    • Doing so tells the tool that you want to edit the membership for the pelvis on the body skin.
    • – CLICK + DRAG to add CVs to the joint influence.
    • NOTE: Edit Membership Selection SHORTCUTS

      • – Deselect Points: CTRL + DRAG
      • – Add Points: CTRL + SHIFT + DRAG.
      • Be careful when deselecting points. Doing so will remove all influence from a given point, if it had some influence from another joint.
  3. More Rigid Binding
    • Geometry that is not intended to deform can be rigid bound to a particular joint. Bind a surface to a selected joint to prevent any deformation.
    • ANIMATION || Skin > Bind Skin > Rigid Bind >
      • Rigid Bind Options:
      • – Bind To: Selected Joints.
      • – RIGID BIND OPTIONS (window) || Edit > Save Settings;
      • – Click [CLOSE]
    • – Rigid Bind the beakTop to the head joint. Select the beakTop first.
    • – Rigid Bind the hair to he head joint.
    • – Rigid Bind the beakBottom to the jaw joint.
    • – Rigid Bind the leftupper leg to the lLeg joint.
    • – Rigid Bind the left knee and shin to the lKnee joint.
    • – Rigid Bind the left ankle to the lAnkle joint.
    • – Repeat to the right leg.
    • Note: You can parent the geometry directly in the skeleton but it’s preferred to keep the setup and geometry in separate hierarchies. You could also parent constrain the geometry to it’s joints, but that wouldn’t allow you to scale the entire setup
    • 052412_17-nurbsRigging_01.ma
  4. Other Skinning
    • Bind the toes and the thigh to more than one joint.
    • – Select the geometry for one of the toes, then SHIFT + SELECT each related toe joint except for the tip.
    •  – Rigid Bind the selection.
    • – Edit the Member ship of each  toe so it bends properly.
    • – ANIMATION || Edit Deformers > Edit Membership Tool
    • – Select the Toe Joint closest to the ankle. Vertices affecting that joint will be highlighted. Yellow shows it’s being affected while brown isn’t.
    • – If you select all 3 or 2 joints for the toes, you’ll notice the shape by he ankle moves up when you rotate. That’s wrong.
    • Use the membership tool. Select the toe joint closest to the ankle and deselect the vertices by holding CTRL + CLICK DRAG over them.
    • – Rigid Bind the thigh to both the pelvis and leg joints.
      • – Select the upperleg joint and check what geometry it’s affecting. It should only be affecting the upperleg geometry. Use the Edit Membership Tool to correct it if it’s not.
      • – Select the thigh geometry, then SHFT + CLICK the pelvis geometry, and then SHFT + CLICK the upperleg joint.
      • – Rigid Bind the selection. Rotate the thigh. it should look like so.
  5. Eye Skinning
    • The eyeballs need to be skinned to the tip of a joint, therefore, you cannot use rigid binding. You will have to smooth bind the eyes to their respective joints.
    • – Select the left eyeball geometry and lEye joint.
    • – Select ANIMATION || Skin > Bind Skin > Smooth Bind > □
      • Smooth Bind Settings
      • Bind to: Selected Joints
      • – CLICK [BIND SKIN]
    • – Repeat for the other eye.
  6. Test the Binding
    • – Translate the pelvis to make sure all the geometry is following. If not, use the edit membership tool to add the vertices that aren’t affected. The Edit membership Tool is funky. With the tool activated, first select the geometry then CLICK on the joint that’s supposed to be affecting it.
    • – Pose the character to see if you need to change something in your skinning.
  7. Save your work
    • – 082412_17-nurbsRigging_02.ma

Animation Rig

  • Create a character rig for similar to one you made for the Penguin in the second project.
  1. Rigging the Legs
    • – Set up the legs using Rotate Plane IKs and pole vectors.
    • NOTE: