1. Object Manipulation Observations 1. Most objects attached or connected to other objects 2. Objects easier to position if in contact with others 3. Objects do not interpenetrate 4. Occlusion most important to judge 3D position 5. Use entire area of visual overlap of the moving object with static scene. 6. Only visible objects can be manipulated 7. "Handles" and wireframe/orthognal view confuse 8. 3D or 6D input devices less precise than 2D

2. New 3D Movement Technique Traditional technique (using mouse cursor position): New technique (using moving object area) Modification (using foremost plane behind moving object)

3. SESAME - Sketch, Extrude, Sculpt And Manipulate Easily Objects slide on visible surfaces & don’t collide View dependent manipulation Suggestions for precision Grouping technique for composite object manip. 3-button mouse + normal monitor