2ObjectivesExplain the importance of pictorial drawings as an aid in visualizationCreate an isometric drawing of an object composed of principal, inclined, and oblique surfacesDraw ellipses on the front, top, and right faces of the isometric to represent cylinders and holes
3Objectives (cont’d.)Explain the difference between a cavalier and cabinet oblique drawingCreate an oblique drawing given the orthographic drawing of an objectCreate a two-point perspective drawing given the orientation of the plan view and the location of the elevation view
4Introduction Pictorial drawings can help visualize a 3-D object Also important when assembling parts into mechanisms or purchasing replacement partsNot used as working drawingsMany types and variations
5Axonometric DrawingsFIGURE Three visible normal surfaces (frontal, horizontal, and profile) of a prism have equal angles between them (120°) in an isometric drawing.FIGURE In a diametricdrawing, two of the three visiblenormal surfaces (frontal andprofile) of a prism have edgespresented at equal angles, notequal to 120°.
6Axonometric Drawings (cont’d.) FIGURE A trimetric drawing presents the three visible normal surfaces (frontal, horizontal, and profile) of a prism in a position where none of the angles between the surface edges is equal.
7Isometric Drawing FIGURE 12.07. The isometric axes. FIGURE Orthographicviews of a step block.
8Isometric Drawing (cont’d.) FIGURE The steps to draw an isometric pictorial of the step block.
9Inclined SurfacesFIGURE Orthographic views of a step block with an inclined surface.
10Inclined Surfaces (cont’d.) FIGURE The step involved to create an isometric pictorial of a step block with an inclined surface.
11Oblique SurfacesFIGURE Orthographic views of a step block with an oblique surface.
12Oblique Surfaces (cont’d.) FIGURE The steps involved to create an isometric pictorial of a step block with an oblique surface.
13Cylindrical SurfacesFIGURE An isometric cube showing ellipses on each face. Note the orientation of the long (major) axis for the ellipse on each of the three normal faces.
14Cylindrical Surfaces (cont’d.) FIGURE Drawing an ellipse on the top isometric surface using the traditional four-center method.
15Cylindrical Surfaces (cont’d.) FIGURE Drawing anellipse on the left isometricsurface using the traditionalfour-center method.
16Ellipses on Inclined Surfaces FIGURE Steps 1 and 2 to create an isometric pictorial showing a vertical circular hole in an inclined surface.
17Ellipses on Inclined Surfaces (cont’d.) FIGURE Steps 3 and 4 to create an isometric pictorial showing a vertical circular hole in an inclined surface.
18Ellipses on Inclined Surfaces (cont’d.) FIGURE Steps 5 and 6 to create an isometric pictorial showing a vertical circular hole in an inclined surface.
19Ellipses on Inclined Surfaces (cont’d.) FIGURE The finishedconstruction of the verticalcircular hole in an inclinedsurface.
20Oblique Drawings Types of oblique drawings FIGURE A cabinet oblique pictorial.FIGURE A cavalier oblique pictorial.
21Construction of Oblique Drawings FIGURE The stepsrequired to construct an oblique pictorial.
22Construction of an Object with Circular Features FIGURE The steps required to construct an oblique pictorial with circular features.
23Perspective DrawingsFIGURE An illustration showing railroad tracks converging to a vanishing point on the horizon.
24Types of Perspective Drawings FIGURE An example of a two-point perspective drawing.
25Types of Perspective Drawings (cont’d.) FIGURE An example of athree-point perspective drawing.
26Two-Point Perspective Drawings FIGURE The relationship between the PP and the object.
27Construction of a Two-Point Perspective Drawing FIGURE Establishingand marking the left and rightvanishing points.
28Construction of a Two-Point Perspective Drawing (cont’d.) FIGURE Establishing the ML.
29Construction of a Two-Point Perspective Drawing (cont’d.) FIGURE Drawing the visual rays of the object to the PP through the SP.
30Construction of a Two-Point Perspective Drawing (cont’d.) FIGURE Completion of the perspective.
31Complex Object in Two-Point Perspective FIGURE A two-point perspective drawing of a complex object.
32Considerations for 3-D Modeling Easiest way to create pictorial drawings is to extract from solid modelsUsually matter of specifying viewing orientation and amount of perspectiveVery easy to extract
33SummaryUsed pictorial drawings for visualization and understanding 3-D relationships of objectsCreated isometric drawings for simple communication
34Summary (cont’d.)Introduced oblique drawings, which are very quickly and simply createdUsed perspective drawings for applications that demand the most realistic appearance