CSE 490 J - Character Pre-Production for 3D Animation

Assignment #4: Grey Model Pose Test

Start from the finished grey model scene from the last assignment.

Part 1: Skin Weighting

Save your file as "assignmen4_skin_weights" file type .ma

1. Prepare the grey model for skin binding
   1. Select the mesh
   2. Freeze Transformations, Modify → Freeze Transformations
   3. Delete History, select the mesh, Edit → Delete All By Type → History
   4. Rename the model "grey_model"
   5. Delete any unused nodes in the scene using the Outliner or Hypergraph
      
      
2. Apply Smooth Bind
   1. Select the bind joints
      • Select center_root_bind_joint
      • Select Hierarchy, Select → Hierarchy
      • Deselect the end null joints.  Use Ctrl-click to deselect them in the Outliner or Hypergraph
   2. Shift-select the grey model
   3. Go to the smooth bind options:  Skin → Bind Skin → Smooth Bind [options]
   4. Set the options to match the screenshot and press Apply
      
      
   5. After binding the model to the skeleton, DO NOT DELETE HISTORY!
      It will remove the skinCluster node added to your grey model and thus all of the weights.
      
      
3. Paint Skin Weights
   Start with the shoulder, then repeat for the rest of the body
   
   
   1. Set keyframes on the shoulder joint to test the range of motion
      • Select right_upperarm_bind_joint and set a keyframe on frame 1. ("s" hotkey will set a keyframe)
      • Move the time slider forward to frame 10.  Rotate the shoulder up and set another keyframe.
      • Move the time slider forward to frame 20.  Rotate the shoulder backward and set another keyframe.
      • Scroll the time slider while painting weights to test the skin deformations in different poses.
   2. Paint the skin weights so the bulge on the inner torso becomes flat
      • Right-click on the mesh and choose Paint Skin Weights Tool
      • Right-click over the chest joint and choose Select Influence
      • Set your Paint Skin Weights tool options as follows:
      • [Paint operation = Add, Opacity ≈ 0.1, Use Color Ramp = False]
        
        
        
        
   3. Use the brush on the mesh to paint the chest area to not be influenced by the shoulder.
      
      

      Before

      After

      
      

      Repeat this step for the rest of the body until the model looks good when the skeleton is animated.
      

   4. Use the "flood" option on the Paint Skin Weights tool to fix the head.
      1. Set a keyframe on the head joint on frame 1 ("s" hotkey will set a keyframe)
      2. Move the time slider forward to frame 10 and set a keyframe with the head joint rotated back. - notice that the head deforms incorrectly with the joint rotated.
      3. Select all vertices on the head
      4. In the Paint Skin Weights tool set the options to:
         1. Paint Operation=Replace, Opacity=1,
         2. With the head joint highlighted in the tool window, press Flood
         3. Use the Smooth brush to clean up the transition

   

-- Before

-- After

 

Tip: When you're done with one side you can mirror the skin weights over to the other side

• Skin → Edit Smooth Skin → Mirror Skin Weights
• [Mirror across =YZ, If you worked on the right side of the character uncheck "Postive to negative"]

Part 2: Grey Model Pose Testing

1. First, delete all keyframes that were made for testing skin weights in the above steps.
   1. Move the time slider back to the first frame
   2. Edit → Delete All by Type → Channels
2. Keyframe the skeleton in the bind pose on frame 1
   1. Select the model and press: [rigging menu set] Skin → Go To Bind Pose
   2. Select all joints in the skeleton using this button on the Character Design shelf
   3. Set a keyframe using the "s" hotkey
3. Keframe the skeleton in the crouch pose on frame 10
   1. Move the time slider forward to frame 10
   2. Rotate joints (and translate the root joint) into the crouch pose. This should look the same as the crouch pose from the block model pose test with arms forward.
   3. Select the skeleton and set a keyframe.
4. Make 3 or more "character" poses that demonstrate his or her personality. Set keyframes for these every 10 frames, starting on frame 20.

Here are some examples of character poses I made for my character, Micah the longboarder. You can model a prop if you want to, but that is not required. Only make a prop if it is really important to your character's identity.

Use these poses to polish your skin weighting. Scroll the time slider between the poses and see how well you can keep volume preserved by adjusting the skin weighting. You might find out that you need to change the way the model or skeleton are built! Take note and we will make those changes in the next assignment.

Save your file

• assignment4_skin_weights.ma
• Save out screenshots for each of the test poses
  • assignment4_pose1_bindpose.png (or .jpg)
  • assignment4_pose2_crouch.png (or .jpg)
  • assignment4_pose3_character.png (or .jpg)
  • assignment4_pose4_character.png (or .jpg)
  • assignment4_pose5_character.png (or .jpg)
    
    

Grading Rubric

For this assignment we will be checking to make sure that the following elements of the assignment are present in your submission:

NOTE: 2 points will be subtracted for incorrect file names and formats

Turning in your files

Like last time you will be turning your files into Canvas. For this assignment, turn in the following:

1. assignment4_skin_weights.ma
2. assignment4_pose1_bindpose.png (or .jpg)
3. assignment4_pose2_crouch.png (or .jpg)
4. assignment4_pose3_character.png (or .jpg)
5. assignment4_pose4_character.png (or .jpg)
6. assignment4_pose5_character.png (or .jpg)

Your assignment is due Wednesday, August 7th at 9:00 PM.