1. Don Slater dslater@andrew.cmu.edu Wanda Dann wpdann@andrew.cmu.edu Joint Operations Copyright 2012 Wanda Dann, Don Slater All rights reserved

2.  Objects often (not always) have internal joints that can be animated to control subparts of the model.  A joint connects a subpart of the body to the rest of the body  A joint can be turned or rolled but cannot be moved Internal Joints

3. Biped X-ray

4. Quadruped X-ray

5.  A subpart may be connected to another subpart  Rotating one subpart may also rotate other subparts  Examples:  Turning the left shoulder joint will turn the entire arm of the alien, including the forearm, wrist, hand, fingers, etc.  Turning the left elbow joint will turn the alien’s forearm, wrist, hand, fingers, etc. Subpart Location Connected subparts

6.  To access a joint, click on the arrow next to the object’s name in the instance list. In the Code Editor

7. In the Scene Editor By clicking on Show Joints and adjusting the opacity in the Scene Editor, you are able to see the joints of any model.

8. Add axes object to the scene Move and orient the axes to the joint The white axis points forward, red to the right, green up Orientation of a joint

9. Orientation: whole vs. part The orientation of a subpart is not necessarily the same as the orientation of the whole object.

10.  A subpart cannot be moved  A move would detach the joint (and its connected subpart) from rest of the model, so a move action is NOT allowed for a subpart of an object. Translational Motion: Joints

11.  A subpart’s joint acts as its pivot point for rotation of the subpart.  Two forms of rotational motion:  turn  forward, backward  left, right  roll  left, right Rotational Motion: Joint/Subpart

12. Rotation of a joint

13. Turn forward/backward Red Handle: Turns joint forward and backward

14. Turn left/right Green Handle: Turns joint left and right

15. Roll left/right Blue Handle: Rolls joint left and right