point of view
DESCRIPTION
Point of View. An object’s Point of View comprises its position and orientation. Position tells us where the object is in the world. Orientation tells us the direction an object is facing. - PowerPoint PPT PresentationTRANSCRIPT
Fall 2009 ACS-1805 Ron McFadyen 1
Point of View• An object’s Point of View comprises its position and
orientation. • Position tells us where the object is in the world. • Orientation tells us the direction an object is facing.
• An object’s position is given by 3 values: location in the world’s LR axis, location in the world’s FB axis, location in the world’s UD axis. See the pointOfView.position property values.
• An object’s orientation is given by 3 values: yaw, pitch, roll. Yaw is the objects rotation about the UD axis. Pitch is the object’s rotation about the LR axis. Roll is the object’s rotation about the FB axis.
• See The PointOfView property for objects
Fall 2009 ACS-1805 Ron McFadyen 2
Orientation of objects
• Each object has its own coordinate system that provides its own sense of direction
• If Bob is asked to turn left ¼ revolution, Bob’s sense of direction turns with him
forward
forward
Bob
Note here that Bob rotated on his up-down axis. An object’s yaw is how much the object is rotated along this up-down axis since its original position.
Fall 2009 ACS-1805 Ron McFadyen 3
Orientation of objects
• Bob had just turned…
• Now if we ask Bob to move forward, Bob advances along the forward-backward axis
forward
forward
Fall 2009 ACS-1805 Ron McFadyen 4
Orientation of objects
• Bob had moved forward…
• Now if we ask Bob to turn forward, Bob rotates on the left-right axis
forward
forward
right
Note here that Bob rotated on his left-right axis. An object’s pitch is how much the object is rotated along this left-right axis since its original position.
Fall 2009 ACS-1805 Ron McFadyen 5
Orientation of objects
• Consider Bob back at …
• Now if we ask Bob to roll left, Bob rotates on the forward-backward axis
Note here that Bob rotated on his forward-backward axis. An object’s roll is how much the object is rotated along this forward-backward axis since its original position.
forward
forward
Fall 2009 ACS-1805 Ron McFadyen 6
Orientation of objects
• Each object has its own coordinate system that provides its own sense of direction
• If Dave and Peter are asked to move forward, they go in opposite directions
• You reset an object’s coordinate system by using orient to to give both the same sense of direction
• Dave orient to Peter
forwardforward
forwardforward
Dave Peter
Fall 2009 ACS-1805 Ron McFadyen 7
Orientation of objects
• You reset an object’s coordinate system and location by using set point of view
• Dave set point of view Peter
forwardforward
forward
Dave Peter
Fall 2009 ACS-1805 Ron McFadyen 8
Move, Turn, Roll
Action Parameters Sample object
Move left, right, forward, back, up, down any object
Turn left, right, forward, back door
Roll left, right knob, dial
forward Dave
Fall 2009 ACS-1805 Ron McFadyen 9
Move, Turn, Roll
Move Turn Roll
e.g. lid dial knob
door
Fall 2009 ACS-1805 Ron McFadyen 10
Arguments
• Duration: the default length of time for an action is one second – this can be modified
• Style: the smoothness of an action is controlled using one of the values begin gently, begin abruptly, end gently, end abruptly
• As seen by: the sense of direction (orientation) for an action is by default determined by the object that is acting, but this can be changed by specifying a different object to use for direction