Presentation on theme: "Fundamentals of Engineering"— Presentation transcript:
1Fundamentals of Engineering Isometric Sketching and Coordinate SystemsGSMSTObjectives:
2Objectives Define 2D and 3D coordinate systems Determine coordinates of objects in:2D views3D viewsPractice drawing isometric from orthographicObjectives:Co-ordinate systems & object design - At the end of the session, students should be able to:Determine coordinates of vertices in 3-D space, given 2-D orthographic projection sketchesDevelop 3-D isometrics given coordinate of vertices in 3-D spacesApply coordinate systems to effectively transform orthographic projections to isometricsDemonstrate the knowledge of isometric and orthographic projection by creating a problem
3Pictorial Sketching: Coordinate Systems Y Used to define the locations of points, lines, and planes in 2 or 3 dimensions."Cartesian Coordinate system"YX
4Coordinate Space in 2-DA 2-D coordinate system locates the origin at the intersection of the X axis (horizontal axis or abscissa) and the Y axis (vertical axis or ordinate).These are called View Coordinates.X-X-YY
6Coordinate Space in 3-DZXY-Z-X-Y(0,0,0)In the 3-D coordinate system (world coordinate system) the axes are mutually perpendicular.The origin (0,0,0) is usually taken at the intersection of these axes.
73-D Coordinate SystemsConsist of three, mutually perpendicular axes used to define spacePositive or negative based on the axesRight Hand Rule determines if a coordinate system is positive (right-handed) or negative (left- handed)3-D Coordinate systems are generally positive (right-handed)
8Coordinate Systems: Right Hand Rule Place your fingers in the direction of the positive x-axis and rotate them in the direction of the y-axis. Your thumb will point in the direction of the positive z-axis.
9Left or Right-Handed? The systems are right-handed (positive). ZXYYZXThese systems are left-handed (negative).ZXYYXZ
10Orthographic Projection: Missing Views Constructing the third view helps visualization skills. When constructing the third view, recall:Points project perpendicularly from one view to thenext.Object dimensions (height, width and depth) are preserved from one view to the next.17
11Orthographic Projection: Missing Views Two Solutions 18
12Pictorial SketchingUsed to portray a 3-D object on a 2-D sheet of paper.3-D axes appear differently when shown on a 2-D surface.Standard axes:IsometricOblique
13Oblique SketchingSince one face of the object is undistorted, the most irregular face is usually shown in the plane of the paper.
14Oblique Sketching 3 types of oblique pictorials. Cabinet pictorials are the most common.
18To draw oblique sketches: 1. Draw the first surface completely 2 Oblique Sketching31To draw oblique sketches:1. Draw the first surface completelyAdd lines showing the receding dimension (depth)3. Repeat until the object is completeNotice: All receding lines are parallel to one another
19Oblique PracticeTask: Using engineering paper, draw both these coded sketches.3World coordinates are tied the 3D representation of the object. Each orthographic view shows only 2 of the three coordinates at a time.1
20Isometric Coordinate Axes Isometric sketches are made as if you’re looking down a diagonal a cube
21Isometric Coordinate Axes Note: all isometric object surfaces will appear distorted.Square surfaceappears as a rhombusIsometric sketches are made as if you were looking down a diagonal of a cube
22Isometric Coordinate Axes Isometric grid paper/dot paper is useful for constructing isometric drawings.We'll use grid paper in class and dot here in the PowerPoint
23Coded Plans Pictorial sketches can be made from coded plans. Coded plans define the shape of a block building."Arrow" shows the corner you are drawing fromCoded PlanBuilding
25Isometric Sketching 0.Draw edge "C“ 1.Sketch right or left surface. 3121CGuidelines for constructing isometric drawings:CStep 1 & 2Step 3Step 4 ...0.Draw edge "C“1.Sketch right or left surface.2.Draw a surface that shares an edge with the surface just drawn.3.Continue drawing one surface at a time until the object is complete.Step 4 ...
26Isometric PracticeTask: Using isometric paper, draw these coded sketches.World coordinates are tied the 3D representation of the object. Each orthographic view shows only 2 of the three coordinates at a time.
27Orthographic and Isometrics Coordinates XZYTask: Using the worldcoordinates conventionfor computers and CAD,determine the values of the coordinates for points in orthographic drawings and isometric drawings.Note the origin (0,0,0) can be set at an any point.World coordinates are tied the 3D representation of the object. Each orthographic view shows only 2 of the three coordinates at a time.
28World Coordinates in Orthographic Projections BCDYXAAX Y ZTake time to explain the oblique cut across the upper part of the body. Students have a difficult time when seeing this for the first time. Demonstrate how to identify its coordinates.Note C to D is a straight line.Note some students may find it easier to do the isometric for visualization and then do the coordinates. Encourage students to do it the way that works for them.ZXZY
29World Coordinates in Isometric Projections BXZYBACDYXAAX Y ZExplain to the students how the coordinates are transformed from the 2D to the 3D drawing. Make it clear how to travel along each of the three axes to properly count coordinates in the 3D space.ZXZY
30World Coordinates in the Isometric What are theCoordinatesOf this point?X Y ZAXZYThe solution appears with a second click of the mouse. This is helpful to students to visualize the 3D coordinates for oblique surfaces.
31Orthographic Views from Isometric Sketches Orthographic Projection:Orthographic Views from Isometric SketchesMake an orthographic sketch, by sketching top, front and right side views of the object shown below.2311
32Isometric Sketches from Orthographic Views Orthographic Projection:Isometric Sketches from Orthographic ViewsSometimes you are asked to constructisometric sketches from orthographic views.Orthographic views develop visualization skillsThe box method is one way to do this.For some problems, the box method may notbe very helpful.
33Iso. Sketches from Ortho Views Orthographic Projection:Iso. Sketches from Ortho Views1. Find the object's overall dimensions from the orthographic views and sketch that size box on isometric dot paper.W
34Iso. Sketches from Ortho Views Orthographic Projection:Iso. Sketches from Ortho Views2. Sketch the top, front, and right side views in their appropriate locations on the box.
35Iso. Sketches from Ortho Views Orthographic Projection:Iso. Sketches from Ortho Views3. Add/remove lines until the view is complete.