bruce mayer, pe registered electrical & mechanical engineer bmayer@chabotcollege

[email protected] • ENGR-22_Lec-13_Aux_View-1.ppt1

Bruce Mayer, PE Engineering 22 – Engineering Design Graphics

Bruce Mayer, PERegistered Electrical & Mechanical Engineer

[email protected]

Engineering 22

AuxiliaryAuxiliaryViews-1Views-1



Chp7 Learning GoalsChp7 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 - GraphicallyAuxiliary 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

• 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

P

Note Folding Line is PARALLEL to Inclined Surface P



Auxiliary Vs. Principle ViewsAuxiliary 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 MethodRecall 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



Aux View Construction – Fold LnAux View Construction – Fold Ln

1. For the Given Example Drawing With H/F Fold Line

2. Select a Direction (Line) of Sight (LoS) Perpendicular to The NonOrthographic Surface

3. Draw Folding Line F/1 Perpendicular to the LoS

4. Project Perpendicular Lines Across the Folding Line To Transfer Feature Distances Used to Construct The Aux-View. Label Vertices if Needed



Aux. V. Construction SummaryAux. V. Construction Summary

Front Side

1. Determine the Line of Sight sight Necessary To Produce The Desired Auxiliary View

Show in TS



Aux. V. Construction SummaryAux. V. Construction Summary

Project eachpoint

L.O.S.

2. Identify surfaces on the object. Locate vertices by Dist –Xfer and project to Aux-V.

Fold

LIneA

F



Vertex NumberingVertex 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 ViewPrimary 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 PlanesProjection 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



LinesLines

A true length line which is PERPENDICULAR to a fold line will appear as a POINT in the adjacent view

X

A line which is Parallel to a fold line will appear TRUE Length in the adjacent view

TLTL

TL



LinesLines

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



SurfacesSurfaces

TS

TS

EV

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



Aux. View ClassificationAux. View Classification

DEPTH of the Object Shown in TRUE LENGTH

HEIGHT of the Object Shown in TRUE LENGTH

WIDTH of the Object Shown in TRUE LENGTH

Proj from FRONT

View

Proj from TOPView

Proj from SIDEView



Reverse ConstructionReverse 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



Reference PlanesReference Planes

The Location is ARBITRARY → Drawer Chooses• Typical Locations → CenterLine, Object EDGES

A REFERENCE Plane is formed by moving the FOLD LINE INTO the body of the object



Partial Auxiliary ViewsPartial 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.



Auxiliary SectionsAuxiliary Sections

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



Descriptive GeometryDescriptive 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

1. Auxiliary view to show the true length of a line.

2. Auxiliary view to show the point view of a line.

3. Auxiliary view to show the edge view of a plane.

4. 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

TL

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)



True Size of a Surface

TL

TL

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.



Dihedral Angles

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

EVEV EV

EV



AutoCAD ExampleAutoCAD 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 SuperScriptNotation to Indicate View



autoCAD Example - SolutionautoCAD 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.2AutoCAD 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

NOTE: Aux-View No. 1 is a.k.a. “1-Space”

ConnectDots



AutoCAD Example – Solution.3AutoCAD Example – Solution.3

TRUE Size

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



AutoCAD Example – Solution.4AutoCAD Example – Solution.4

42dAcirle

Scale Diameter• [1 dwg-mm] = [160 RealWorld-mm]

mmmRWmmdwg

mmRWmmdwgdreal 68.77680

1

16048

Finally the Real World Area

22 32.46468.7 mmA

Calculate REAL-World Area for Circle

For Any Circle



aCAD Example – Distortion FactoraCAD Example – Distortion Factor Use CAD To Calc The Area of the FrontV

(ForeShortented) and AuxV (True Size) Triangles

Calc Linear Foreshortening Factor

%06.93627543 TSFS AADF



All Done for TodayAll Done for Today

AuxilliaryViews

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



Bruce Mayer, PELicensed Electrical & Mechanical Engineer

[email protected]

Engr/Math/Physics 25

AppendiAppendixx

6972 23 xxxxf

bruce mayer, pe registered electrical & mechanical engineer bmayer@chabotcollege

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