Thiết kế flash - Orthographic projections

Orthographic ProjectionsOrthographic Projections Parallel projection techniqueProjectors normal to projection plane Projection PlaneProjectorsNOTE: CAD Systems typically use orthographic projectionOrthographic Projection CategoriesAxonometricThree object faces visibleNo principal axes parallel/perpendicular to projection planeMultiviewOnly one object face visibleOne object face (i.e., two principal axes) parallel to projection planeAxonometric Projections Trimetric – no equal anglesAll principal axes foreshortened unequallyClassed according to angles made by principal axes when projected onto projection planeDimetric – two angles are equalTwo principal axes are equally foreshortenedIsometric – all angles equal (iso  equal, metric  measure)All principal axes foreshortened equally Axonometric Projection ClassesAxonometric Projection ClassesTop ViewFront ViewFront View- Axes OnlyIsometric ScalingLines parallel to any principal axis are foreshortened equally ( scaled proportionally)Measurements can be made parallel to any of the three principal axes NOTE: In a trimetric projection, measurements along a given principal axis are proportional; however, measurements along different principal axes are not scalableIsometric ProjectionsAll 3 principal axes equally foreshortened  same scaleCan be visualized as looking down the diagonal of a cube Trimetric Projection Isometric Projection Isometric DrawingsEach axis is foreshortened to approximately 82% of its true length To correct for this, an isometric projection can be plotted at a scale of 1/.82 (~1.22). This convenient approximation of an isometric projection is called an isometric drawing It can be shown that, in an isometric projection:Isometric ViewingAbout a vertical axis (45 ± 90n)º (n is an integer), thenAn isometric projection is obtained by rotating the view:Out of the horizontal plane, ±35.26ºFrontFront, SideTop, Front, SideIsometric SketchingIn sketching an isometric view, principal axes are aligned as shown below: Orthographic Projections