Several bones in a typical biped skeleton are mirrored by another bone on the opposite side of the body. For example, the right upper arm is mirrored by the left upper arm, the right foot is mirrored by the left foot. Many skeleton naming conventions assign identical names to these mirrored bones, except for a part of the name that indicates whether it lies on the character’s right side or left side. For example, the right forearm is Character_R_ForeArm, and the left forearm Character_L_ForeArm.

If the naming convention you use in your skeleton follows this kind of standard, you can use mirror matching mode to map mirrored bones automatically. (See Define an existing skeleton for HumanIK.)

To activate mirror matching mode

1. Do one of the following in the Characterization Tool.
   • Select Edit > Mirror Matching.
   • Click in the toolbar.

   As you map bones with mirror pairs on the opposite side of the body, the tool checks the name of the selected bone to see whether it contains any of a preset list of substrings commonly used to indicate that a bone lies on the left or right side of the body. If it finds one of these substrings, it looks for another bone with the same name as the current bone, but with the mirror pair substring corresponding to the other side of the body. If that bone is found in the skeleton, it is automatically mapped to the corresponding node on the other side of the body.

   For example, if you map the right elbow node to a bone named Character_R_ForeArm, the Characterization Tool toolbar replaces the R_ with L_, and maps the bone named Character_L_ForeArm (if it exists) to the left elbow node.

If you use a different substring in your bone naming conventions to indicate the left and right sides of the body, you can add a new pair of substrings to the list that are checked by the Characterization Tool.

To configure the substring pairs used in mirror matching

1. Click the mirror matching icon in the Characterization Tool toolbar and select Configure Mirror Matching from the pop-up menu, or select Edit > Configure Mirror Matching to open the Configure Mirror Matching window.

   This window contains a list of all sub-string pairs currently configured for mirror matching mode.

2. In the Configure Mirror Matching window, do any of the following:
   • To add a new pair of substrings, click the + button to add a new row to the table. Enter the substrings for the left and right sides of the body in the new row.
   • To remove a pair of substrings, select the row in the table that you want to remove, and click the - button.
3. Click OK when you have finished configuring the substring pairs.