Thiết kế flash - Perspective projection

Perspective ProjectionPerspective Projection CharacteristicsCenter of Projection (CP) is a finite distance from objectProjectors are rays (i.e., non-parallel)Vanishing pointsObjects appear smaller as distance from CP (eye of observer) increasesDifficult to determine exact size and shape of objectMost realistic, difficult to executePerspective SketchHorizon – observer’s eye levelGround Line – plane on which object restsVanishing point – position on horizon where depth projectors convergeProjection plane – plane upon which object is projectedClasses of Perspective ProjectionOne-Point PerspectiveTwo-Point PerspectiveThree-Point PerspectiveView from AboveVanishing PointsObject edges parallel to projection plane remain parallel in a perspective projectionObject edges not parallel to projection plane converge to a single point in a perspective projection  vanishing point (vp)Vanishing point of a principal axis  principal vanishing point (pvp)One-Point PerspectiveOne principal axis cuts projection plane  one principal vanishing pointProjection plane parallel to one principal plane objectimageTwo-Point PerspectiveTwo principal axes cut projection plane  two principal vanishing pointsProjection plane parallel to one principal axis objectimageThree-Point PerspectiveThree principal axes cut projection plane  three principal vanishing points Lateral Movement of CPVarying Distance from CPProjection Plane LocationSize of projected image depends upon location of projection plane with respect to objectVanishing Points RevisitedA vanishing point is found by passing a line through the center of projection, parallel to a set of parallel object edges. The point where the line pierces the projection plane is the vanishing point.objectimagePerspective ProjectionThe End