ASME Y14.3:2003 pdf download MULTIVIEW AND SECTIONAL VIEW DRAWINGS
1GENERAL
1.1 Scope
This Standard establishes the requirements for creat-ing orthographic views for item description. The topicscovered include the multiview system of drawing, selec-tion, and arrangement of orthographic views, auxiliaryviews, sectional views details, and conventional draw.ing practices. Space geometry and space analysis andapplications are included in the appendices for informational purposes.
1.2 ReferencesThe following documents form a part of this Standardto the extent specified herein, The latest issue shall applyASME Y14.1, Drawing Sheet Size and FormatASME Y14.1M, Metric Drawing Sheet Size and FormatASME Y14.2M, Line Conventions and LetteringPublisher: The American Society of Mechanical Engineers(ASME International), Three Park Avenue, NewYork，NY 10016-5990; ASME Order Department: 22Law Drive，Box 2300,Fairfield,N 07007-2300
ISO 128-30, Technical Drawings – General Principles ofPresentation – Part 30: Basic Conventions for ViewsPublisher: International Organization for Standardization (ISO) 1 rue de Varembe, Case Postale 56，CH1211. Geneve 20,Switzerland/Suisse
1.3 Definitions
adjacent viers: two adjoining orthographic views alignedby projectors.
relafed vieus: two views that are adjacent to the sameintermediate view.
true geometry vieus: views that show the actual shapedescription, and when it is a section view it shows theactual shape cut by the cutting plane.
1.4 Orthographic Projection
Orthographic projection is a system of drawing com-posed of images of an object formed by projectors fromthe object perpendicular to desired planes of projection.
1.5 Orthographic View
An orthographic view is the figure outlined upon theprojection plane by means of the system of orthographicprojection. Such a view shows the true shape of a surfaceparallel to the projection plane (area ABCD with holein Fig. 1). When an area is not parallel to the plane, theview of the area will be foreshortened (area BCEF inFig. 1).
1.6 Projection Systems
The two internationally recognized systems of projection are third angle projection and first angle projection.Unless otherwise stated, this Standard features thirdangle projection.
1.6.1 Third Angle Projection. Third angle projectionis the formation of an image or view upon a plane ofprojection placed between the object and the observerThird angle projection is the accepted method used inthe United States. See Fig. 2.
1.6.2 First Angle Projection. First angle projectionplaces the object between the observer and the planeof projection. This method of projection used in somecountries is herein described, in consideration of theneed to interchange engineering drawings in an interna-tional market. See Fig. 3.
16.3 View Relationships. Note that the orthographicviews of the object have the same configuration in boththe first and third angle projections, but the placementof the views with respect to one another is different. Thevisibility of lines is always taken from the observer’spoint of view. See Figs. 4 and 5.
1.6.3.1 Alternative Practice，Reference ArrowMethod. When it is desired to achieve compliance withISO practices, reference arrows and view letters may beused for all views. These practices are in agreement withISO 128-30.View identification for the reference arrowmethod does not include the word VIEW, and the identi-fying letter is placed above the view. Reference arrowsmay be shown in the CAD model, in an axonometricview, or on one of the principal orthographic views.When the reference arrow method is used, it shall beused for all views within the drawing. See Fig. 6. Reference arrow proportions are defined in Fig. 7