Presentation on theme: "Visualization and Graphics Introduction"— Presentation transcript:
1 Visualization and Graphics Introduction Drafting, Sketching & Dimensioning
2 Objectives Understanding graphics as a communication tool Technical sketchingFreehandInstrumentComputerProjectionsOrthographicPictorialToday’s objectives are:Sketching and Isometric Pictorials - At the end of the session, students should be able to:Infer that technical drawings are effective tools for communication of technical ideasDifferentiate between multi-view and isometric drawingsDevelop isometric sketches of tangible objects on isometric grid sheetJust doing a brief overview of first two topics. We will spend most of the time on Introduction to Projections in particular isometric projection.
3 VisualizationVisualization is often used as a mode of communication between engineersSketches, tables, graphs, computer generated drawings, blueprints are various ways in which engineers communicate via visual mediums
4 How Would You Describe This? In teams of two, describe using only wordsHow effective is this approach?Instructor:This is an in-class interactive exercise(active learning). Allow students about 5 minutes to discuss with partner and then ask random students to put in words their description. Then ask the class the question shown on the slide.
5 Three Basic Types of Technical Drawings Freehand sketchesInstrument drawingsComputer drawingsIn this class we will focus primarily on Freehand Sketching and Computer Based drawingCAD programs have replaced much of Instrument drawing process.Technical sketches are how engineers “think” and communicate with each other. All the way from napkin session at lunch to formal computer based solid models and flow charts.
6 Introduction to Projections Present 3-D objects with 2-D mediaTwo Basic CategoriesOrthographic PictorialDefinitions:Projection: the process or technique of reproducing a spatial (3-D) object upon a plane or curved (2-D) surfaceOrthographic sketches present the object in a series of projections, each one showing only two of the object’s three dimensions.Pictorial sketches present the object in a single view with all three dimensions representedDiscuss the trade-offs in using any type of projection; some are more realistic, some are easier to draw, and some are easier to interpret by non-technical people
7 Projections: Four Basic Types Note: Isometric is a special case of AxonometricOrthographic ProjectionsAxonometricCourse emphasizes on multi-view (orthographic) and isometric (one type of axonometric pictorial) projections onlyMultiview projections are a collection of 2-D viewsPictorials are 3-DPictorialsObliquePerspective
12 Isometric Drawings The most common pictorials Constructed with the two faces 30 degrees above the horizontalThe axes are 120 degrees between each axisLines that are horizontal are drawn at 30 degreesVertical lines remain vertical
13 Isometric Projection CUBE One type of axonometric pictorial (3-D) projection‘Iso-’ means ‘equal‘metric projection’ means ‘a projection to a scaled measure’The three dimensions are not only shown in one view, but also the dimensions can be scaled from this drawingSTART WITH A CUBEAll of the normal drawing planes (top, front, side) are equally foreshortened or tilted, and all of the major axes (X, Y, Z) are at equal rotations from each other (120 degrees apart), as in the illustration above.And, because all of the major planes are equally foreshortened, all of the measurements in these planes are equal as well as shown above. This means that the same measuring scale may be used in drawing both the width, height, and depth of objects.Isometric means equal measureAll planes are equally or proportionately shortened and tiltedAll the major axes (X, Y, Z) are 120 degrees apart
14 Making an Isometric Sketch Defining Axis30o60oIsometric AxisDerive the axes from a vertex of the cube
16 Isometric Dimensioning Dimension lines are parallel to the isometric axesExtension lines are extended in line with these axes
17 Oblique DrawingsThe front view is draw like it would be using orthographic projectionThe front view shows all features with true shape and sizeThe top and side view are then projected back from the front viewViews can be at any angle15, 30 or 45 degrees are common
19 Oblique Drawings Continued Useful when the front contains more details and features than the side viewA mental image can be created more quickly than with orthographic aloneTwo types of oblique drawingscavaliercabinet
31 Perspective Drawings The most realistic of all pictorial drawings Receding lines in the drawing “meet” at a vanishing point instead of being parallelEliminates distortion at the back part of pictorial drawingsTwo typesparallel (one-point) perspectiveangular (two point) perspective
33 Parallel Perspective (One Point) One face of the object is shown as the front viewLines parallel to the front view remain parallelLines that are perpendicular to the front view converge at a SINGLE VANISHING POINT
34 Angular Perspective (Two-Point) Similar to isometric drawingsOne edge of the object is place in frontThe two faces that meet at this edge recede to DIFFERENT VANISHING POINTSAll lines parallel to each face go to the different vanishing points