Bones<title> <link rel="stylesheet" type="text/css" href="../../style.css" /> </head> <body> <center><h1>Bones</h1></center> <p> The skeletal structure is the most fundamental part of a rig and so we will create it first. We will actually have multiple sets of bones in some cases. For example, for the limbs we will want the option to control them with either FK or IK. We will thus have a FK joint chain, a IK joint chain, and a third joint chain called the "bind" skeleton that blends the two and ultimately deforms the skin. We will try to keep the different parts of our rig segmented so we can rig it in pieces. The different pieces can then be combined later. This is also useful if we want to replace a piece later on. </p> <p> A short reminder of Joint Guidelines: </p> <ul style="font-size: 20px;" > <li>All non-root joints must have a non-zero Translate only in X</li> <li>No joint should have rotation, any rotation should be in joint orient</li> <li>No joint should have scale</li> <li>All joints at the end of a joint chain should have zeroed joint orientation</li> </ul> <ol> <li class="step"> From the side view, use the Joint Tool to create a joint at the hip, knee, ankle, middle of the foot, and tip of the toes. Move the root of the joint chain over so that the chain is inside the middle of the left leg. Rename the joints as follows: </li> <ul style="font-size: 20px;" > <li>left_upperLeg_bind_joint</li> <li>left_lowerLeg_bind_joint</li> <li>left_ankle_bind_joint</li> <li>left_ball_bind_joint</li> <li>left_toe_bind_joint</li> </ul> <br/> <img class="small" src="images/leg_joints_side.jpg" /> <img class="small" src="images/leg_joints_inside.jpg" /> <p/> <li class="step"> <p> We will now create a joint chain for the spine. Start at the middle of the hips and create 6 more joints, following the general shape of the spine. Rename the root joint <strong>cen_root_bind_joint</strong> and the other joints <strong>cen_spine_1_bind_joint, cen_spine_2_bind_joint, cen_spine_3_bind_joint</strong>, etc. </p> <p> Select all the joints in the Outliner and go to <strong>Display → Transform Display → Local Rotation Axes</strong>. You will notice that some of the Y axes point forward. We want them all to point backwards and so go to component mode (<strong>F9</strong>), click the Select Miscellaneous Components button (<img src="images/question.jpg" />), and select the Y axes that are pointing forward. Once you have selected them (They should turn yellow), type "rotate 180 0 0" into the MEL command line at the bottom of the window and hit Enter. This should rotate the axes so that they all point backwards now. </p> </li> <img class="small" src="images/wrong_direction.jpg" /> <img class="small" src="images/spine.jpg" /> <li class="step"> <p> Create a new joint chain for the head with joints at the base of the neck, middle of the neck, and below the ear. When creating the first joint, vertex snap it to the last joint of the spine chain. Rename these joints <strong>cen_neck_1_bind_joint, cen_neck_2_bind_joint, and cen_head_bind_joint</strong>. Make sure all the Y axes are pointing backwards like the spine. Zero out the joint orient of cen_head_bind_joint. </p> <p> Create a single joint at the base of the mandible and name it <strong>cen_jaw_bind_joint</strong>. Create two more single joints and place them at the center of each eye. You can do this by selecting an eye then a joint and then using a Point constraint with Maintain offset turned off. Delete the constraint once the joint has moved into place. Rename the eye joints <strong>left_eye_bind_joint</strong> and <strong>right_eye_bind_joint</strong>. Parent the jaw and both eye joints under the head joint to place them in the hierarchy. </p> </li> <img class="small" src="images/neck1.jpg" /> <img class="small" src="images/neck2.jpg" /> <img class="thumb" src="images/neck3.jpg" /> <li class="step"> In the Front view, create a joint chain with joints at the collarbone, the shoulder, the elbow, and the wrist. To place a joint exactly along an axis from the previous joint, hold <strong>Shift</strong> and then Left-click and drag it to where you want it. Move the root joint so that the chain is in the center of the arm. Name the joints as follows: </li> <ul style="font-size: 20px;" > <li>left_clavicle_bind_joint</li> <li>left_upperArm_bind_joint</li> <li>left_lowerArm_bind_joint</li> <li>left_wrist_pos_joint</li> </ul> <br/> <img class="thumb" src="images/arm.jpg" /> <li class="step"> Duplicate the lowerArm joint and unparent it from the joint chain. With the duplicated joint selected, use the "Split selected joint" script from the Rigging shelf. Set the number of segments to <strong>4</strong>. This should split the joint as shown below. Rename the joints <strong>left_foreArm_1_bind_joint, left_foreArm_2_bind_joint</strong>, and so on. </li> <img class="thumb" src="images/arm_split.jpg" /> <li class="step"> <p> In the Top view, create joint chains for each of the fingers and the thumb. Move the chains up so that they are inside the fingers. You will have to rotate the thumb chain downward, but be sure to Freeze Transformations on it afterward to eliminate the rotate. Rename the joint chains <strong>left_FINGER_#_bind_joint</strong> where FINGER is pinky, ring, index, pointer, or thumb and # is the number of the joint in the chain. </p> <p> Duplicate the left_wrist_pos_joint joint from the arm chain. Unparent it and rename it <strong>left_wrist_bind_joint</strong>. Parent all of the finger chains under this new wrist joint. Be sure to zero out the Joint Orient of the end joints. </p> </li> <img class="small" src="images/hand_top.jpg" /> <img class="small" src="images/hand_bones.jpg" /> <li class="step"> We need to give the joints their correct joint orientation so that the animator can avoid gimbal lock. You can quickly change the Rotation Order of a joint by selecting it and using the "Change Rotation Order On Selected Objects" script. Change to these orders: </li> <ul style="font-size: 20px;" > <li>upperArm: <strong>xyz</strong></li> <li>lowerArm: <strong>xzy</strong></li> <li>foreArm joints: <strong>yzx</strong></li> <li>wrist and finger joints: <strong>zyx</strong></li> <li>spine, neck, head, root: <strong>yzx</strong></li> <li>All leg joints: <strong>xyz</strong></li> <li>eyes and jaw: <strong>zyx</strong></li> </ul> <br/> <li class="step"> We will set the Preferred Angle on a few joints so that they behave properly when IK is applied to them. Preferred Angle can be found above the Joint Orient attribute. Set the lowerArm's Preferred Angle to -25 in the Y. Set lowerLeg's to 25 in the Z. </li> <li class="step"> Select the left clavicle joint and go to <strong>Skeleton → Mirror Joint (Options)</strong>. Select Mirror across <strong>YZ</strong> and Mirror function <strong>Behavior</strong>. Set Search for to <strong>left_</strong> and Replace with to <strong>right_</strong>. Also mirror the leg, foreArm, and wrist joint chains. </li> </ol> <center><a class="large" href="index.html">Back to Project</a></center> </body> </html>