Registered Electrical & Mechanical Engineer BMayer@ChabotCollege.edu Engineering 22 Auxiliary Views-1 Bruce Mayer, PE Registered Electrical & Mechanical Engineer BMayer@ChabotCollege.edu

Chp7 Learning Goals To Develop The Skill to Generate Views That Show Inclined And NonGlassBox (Oblique) Surfaces In TRUE Shape In Multiview Drawings To Be Able to Integrate into Standard MultiView Drawings these AUXILIARY VIEWS to Clarify the Description of The Object

Auxiliary Views AUXILIARY views are often used to show INCLINED and OBLIQUE surfaces in TRUE SIZE. Inclined and oblique surfaces do not show true size in the standard views. Auxiliary views are OrthoGraphic views taken from a direction of sight OTHER than top, front, right side, left side, bottom, or rear. PRIMARY auxiliary views are projected onto a plane that is perpendicular to only one of the PRINCIPAL planes of projection and is inclined to the other two. SECONDARY auxiliary views are projected from PRIMARY auxiliary views.

Auxiliary Views - Graphically Principal faces of the above object are NOT Parallel to the standard planes of projection The auxiliary view shows the TRUE Size and Shape of the hole feature

Glass Box with Auxiliary Plane Note Folding Line is PARALLEL to Inclined Surface P The Aux Plane Shows Surface P in TRUE Size Observe the FORESHORTENING in the Top View The Aux Plane is Perpendicular to the Frontal PLANE

Auxiliary Vs. Principle Views Principle planes Horizontal (Top and Bottom view) Frontal (Front and Back view) Profile (Left and Right Side view) Auxiliary views Definition: An OrthoGraphic view that is projected onto a plane that is NOT parallel to ANY of the PRINCIPLE planes Purpose: To show the TRUE shape of a detail that does not lie in one of the principle planes

Recall Fold-Line Method A Fold Line (Hinge) May Be Placed Between Adjacent Views To Aid In The Construction And Interpretation Of Multiview Drawings Projection Lines Are Always Perpendicular To Fold Lines The Distance From a Fold Line To Any Specific Point On An Object Is The Same For Any Related Views (ex. Top and Side View) CRITICAL for DISTANCE TRANSFER Fold Lines Represent a 90° Rotation In Viewpoint Use Dist-Xfer INSTEAD of Mitre-Line Note that X & Y need NOT be the Same, BUT D1, D2, and D3 are the Same Use to Xfer distance “one View Back”

Aux View Construction – Fold Ln For the Given Example Drawing With H/F Fold Line Select a Direction (Line) of Sight (LoS) Perpendicular to The NonOrthographic Surface Draw Folding Line F/1 Perpendicular to the LoS Project Perpendicular Lines Across the Folding Line To Transfer Feature Distances Used to Construct The Aux-View. Label Vertices if Needed

Aux. V. Construction Summary Determine the Line of Sight sight Necessary To Produce The Desired Auxiliary View Show in TS Front Side

Aux. V. Construction Summary Identify surfaces on the object. Locate vertices by Dist –Xfer and project to Aux-V. Fold LIne A F Project each point L.O.S.

Vertex Numbering Vertex Numbering is More Critical to Aux-View Construction Than to Principle-View Development Recall The Vertex Numbering System From §7.6 in Text If a POINT is VISIBLE in a Given View, Then the Number is Placed OUTSIDE of the Corner If a POINT is HIDDEN, Then Place The Number on the INSIDE of the Vertex

Primary Auxiliary View Definition: Any view that is projected from (adjacent to) one of the principle views and which is not parallel to any of the principle planes A primary auxiliary view is perpendicular to Only ONE of the principle planes ANY INCLINED surface may be shown in TRUE Shape in the Appropriate primary auxiliary view If the fold line for an auxiliary view is PARALLEL to the EDGE VIEW of an Inclined surface then the Inclined surface will appear in TRUE shape in the auxiliary view

Projection Planes A fold line represents the Edge View of the projection plane for the adjacent view (Frontal in this case) A line appears in true-length if it lies in a plane parallel to the projection plane A line which is not parallel to the projection plane appears foreshortened A line which is perpendicular to the projection plane appears as a point

Lines TL X TL TL A line which is Parallel to a fold line will appear TRUE Length in the adjacent view A true length line which is PERPENDICULAR to a fold line will appear as a POINT in the adjacent view

Lines All views adjacent to a point view of a line will show the line in true length A line which does not appear true length in any of the principle views is called an OBLIQUE line

Surfaces A Surface appears in “true shape” (undistorted) if it is PARALLEL to the projection plane A surface appears as an edge parallel to the fold line in all views adjacent to the true shape view of the surface If any line on a surface appears as a point then the surface will appear as an edge A surface which does not appear as an edge in any of the principle views is called an OBLIQUE surface TS TS EV

Aux. View Classification Proj from FRONT View Proj from TOP View Proj from SIDE View View Name taken from the DIM that is NOT shown in the Primary view DEPTH of the Object Shown in TRUE LENGTH HEIGHT of the Object Shown in TRUE LENGTH WIDTH of the Object Shown in TRUE LENGTH

Reverse Construction To Construct a Regular View That Contains ForeShortened Lines/Surfaces or Ellipses It is often More Efficient to FIRST Construct the TRUE-Length Auxiliary view (use dist & offset to xfer “a” or “b”) The Regular View Can then Be constructed Using Std Methods A REFERENCE Plane is formed by moving the FOLD LINE into the body of the object it

Reference Planes A REFERENCE Plane is formed by moving the FOLD LINE INTO the body of the object A REFERENCE Plane is formed by moving the FOLD LINE into the body of the object it The Location is ARBITRARY → Drawer Chooses Typical Locations → CenterLine, Object EDGES

Partial Auxiliary Views Compare to Slide-17 PARTIAL Auxiliary Views are frequently used. The entire view may be unnecessary and often is difficult to read. Partial views should be connected to the view from which it is projected by a centerline or reference line so that it does not appear lost and unrelated to the other views. A break line can be used to indicate that the view is a partial view. To avoid drawing difficult elliptical surfaces

Auxiliary Sections To avoid drawing difficult elliptical surfaces Often An OFF-ANGLE SECTIONAL VIEW is more Informative Than a Normal Projection View. Auxiliary Sections are Constructed by Combining Aux-View Projection Techniques With the Previously Described Sectioning Methods

Must go “One View Back” for Dist-Xfer Descriptive Geometry Gaspard Monge of France Developed “Descriptive Geometry” in Late 18th Century Successive Auxiliary Views Constitute the Basic Technique of DG Must go “One View Back” for Dist-Xfer

Descriptive Geometry cont DG Uses auxiliary views to solve engineering problems. These four auxiliary views are basic to solving problems in descriptive geometry Auxiliary view to show the true length of a line. Auxiliary view to show the point view of a line. Auxiliary view to show the edge view of a plane. Auxiliary view to show the true size of a plane.

True Length of a Line A line will show TRUE length in a plane of projection which is PARALLEL to the line. To show a line in true length, make the FOLD LINE PARALLEL to the LINE in question. Transfer FL-to-Pt distance from “One View Back”

Point View of a Line A line will show as a POINT view when projected onto a plane PERPENDICULAR to a TL View. To show a point view, choose the direction of sight parallel to the line where it is shown in true length (FL is  TL View). Xfer Dist from One View Back

Edge View of a Plane A planar surface will show ON-EDGE in a plane of projection which shows any LINE that lies entirely WITHIN THE PLANE as a POINT view. Choose the direction of sight parallel to a TL line lying in the plane (FL is  to TL Line) TL

True Size of a Surface A surface shows TRUE SIZE when projected onto a plane PARALLEL to it. Choose the line of sight perpendicular to the edge view of the plane. TL TL

Dihedral Angles EV EV EV EV The angle between two planes is called a DIHEDRAL ANGLE Use an auxiliary view to show dihedral angles in true shape → “Sight Down” the Vertex Line

AutoCAD Example Given Triangle ABC and The Associated Frontal & Profile Views Find: True Size Drawing of Triangle ABC The Area of the TS-Triangle Circumscribing Circle Given Scale 1:160 Notice the SuperScript Notation to Indicate View aF→ Point-a in Frontal Space/View

autoCAD Example - Solution Draw Horizontal Construction Lines to Verify Views as Front & Side OK → Draw F/P Folding Line Profile View Shows as STRAIGHT LINE Must be an EDGE VIEW of the Triangle plane

AutoCAD Example – Solution.2 Since Profile View is EV, The LoS for TS will be  to EV Thus Strike P/1 FL to Right of Profile View Using FL P/1 Extend Construction Lines into Aux View In Front-V Measure Offset Distances to Locate Pts in Aux-V Connect Dots NOTE: Aux-View No. 1 is a.k.a. “1-Space”

AutoCAD Example – Solution.3 Draw TS Triangle in Aux View-1  Use Geometric Construction to Make Circle Construct -Bisectors from Two Sides to Locate Circle-Center; use ACAD “3P” option to Draw circ. Use Ruler to measure Circle Diameter on Drawing TRUE Size

AutoCAD Example – Solution.4 Calculate REAL-World Area for Circle For Any Circle Scale Diameter [1 dwg-mm] = [160 RealWorld-mm] Finally the Real World Area 

aCAD Example – Distortion Factor Use CAD To Calc The Area of the FrontV (ForeShortented) and AuxV (True Size) Triangles Calc Linear Foreshortening Factor

All Done for Today Auxilliary Views NORMAL SURFACES are either vertical or horizontal planes that are parallel to the the six principal planes of projection or normal views. INCLINED SURFACES are sloping upward or downward at some angle to the horizontal plane of projection or top view. ANGLED SURFACES are vertical surfaces that are at some angle to the front, back or side views. OBLIQUE SURFACES are at some angle to ALL sides of the object

Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu Engr/Math/Physics 25 Appendix  Time For Live Demo Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu