ENGR1170ENGR1170

AuxilliaryAuxilliary ViewsViews

Auxiliary ViewsAuxiliary Views

Auxiliary views are created in the same way Auxiliary views are created in the same way as other orthographic views but they depict a as other orthographic views but they depict a view from some nonview from some non--orthoortho direction direction

Auxiliary views are most commonly Auxiliary views are most commonly used to show the true size of a surface used to show the true size of a surface that is not parallel to any of the that is not parallel to any of the principal viewing planes principal viewing planes

Auxiliary Views ApplicationsAuxiliary Views ApplicationsTrue size of an inclined or oblique plane True size of an inclined or oblique plane True Length of a lineTrue Length of a linePoint view of a linePoint view of a lineEdge view of a planeEdge view of a planeReverse ConstructionReverse Construction

Auxiliary ViewsAuxiliary Views

SecondarySecondarySingle view projected from a primary Single view projected from a primary auxiliary viewauxiliary view

Primary:Primary:Single view projected from one of six Single view projected from one of six principal viewsprincipal views

TertiaryTertiarySingle view projected from a secondary or Single view projected from a secondary or another tertiary auxiliary viewanother tertiary auxiliary view

The inclined plane ABCD would not have its The inclined plane ABCD would not have its true area in any of these viewstrue area in any of these views

To get the true area we have to look along a To get the true area we have to look along a perpendicular to the planeperpendicular to the plane

Another Auxiliary ExampleAnother Auxiliary Example

Auxiliary Views TypesAuxiliary Views Types

HalfHalfOnly half of an object is drawn Only half of an object is drawn (symmetrical)(symmetrical)

PartialPartialOnly details of the inclined plane are Only details of the inclined plane are projected and drawnprojected and drawn

CurvesCurvesHow do you treat curves?How do you treat curves?

Introduce projection lines that cut the surface and project Introduce projection lines that cut the surface and project these intersections as a typical these intersections as a typical auxialliaryauxialliary projection. See projection. See

diagram below:diagram below:

The reference plane was placed at the center of the The reference plane was placed at the center of the cylinder for conveniencecylinder for convenience

True length of a lineTrue length of a line

Therefore, if a line is parallel to a multiTherefore, if a line is parallel to a multi--view fold line view fold line in one view then that line is a in one view then that line is a true lengthtrue length in the other in the other

view (connected by that fold line).view (connected by that fold line).

A line will show true length in a plane of projection which is A line will show true length in a plane of projection which is parallel to the line. parallel to the line.

To show a line true length, make the fold line parallel to the To show a line true length, make the fold line parallel to the line in question.line in question.

True length of a lineTrue length of a line

In the front view AB is parallel to fold line 2, In the front view AB is parallel to fold line 2, therefore it is a true length line in the side viewtherefore it is a true length line in the side view

Fold line 2Fold line 2Fold line 1Fold line 1

Line as a point Line as a point A line will show as a point view when projected onto A line will show as a point view when projected onto a plane perpendicular to it.a plane perpendicular to it.

To show a point view, choose the direction of sight To show a point view, choose the direction of sight parallel to the line where it is show true length.parallel to the line where it is show true length.

Secondary Auxiliary ViewsSecondary Auxiliary Views

An oblique surface requires An oblique surface requires a secondary auxiliary view a secondary auxiliary view to show the surface in true to show the surface in true shapeshape

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

The top view shows the The top view shows the oblique surfaceoblique surfaceA secondary auxiliary view A secondary auxiliary view is needed to show the is needed to show the surface in true shapesurface in true shapeThe lengths of sides and The lengths of sides and angles are distorted in all angles are distorted in all other viewsother viewsPerpendicular projection Perpendicular projection lines and reference planes lines and reference planes are used to construct the are used to construct the right side view from the right side view from the front and top viewfront and top view

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

A true length line on the A true length line on the oblique surface is oblique surface is identified in the right identified in the right side viewside viewPlacing a fold line which Placing a fold line which is perpendicular to the is perpendicular to the true length line gives the true length line gives the edge view of the surfaceedge view of the surfaceThis auxiliary view is a This auxiliary view is a primary auxiliary viewprimary auxiliary viewThe edge view of the The edge view of the surface is needed to surface is needed to obtain the true shape obtain the true shape viewview

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

A fold line which is A fold line which is drawn parallel to the drawn parallel to the edge view of the oblique edge view of the oblique surface gives the surface gives the secondary auxiliary view secondary auxiliary view showing the surface in showing the surface in true shapetrue shapeReference planes and Reference planes and perpendicular projectors perpendicular projectors are used to determine are used to determine the location of verticesthe location of verticesOften only the inclined Often only the inclined or oblique surface is or oblique surface is shown in auxiliary viewsshown in auxiliary views

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

Simplify the construction of Simplify the construction of drawings by starting with drawings by starting with only a portion of the only a portion of the drawingdrawingThe right side view is The right side view is constructed by using parallel constructed by using parallel projection lines and projection lines and reference planesreference planesVertices are numbered to Vertices are numbered to help keep track of correct help keep track of correct distances from reference distances from reference planesplanes

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

A true length line is identified in the right side viewA true length line is identified in the right side viewline 2line 2--4 is parallel to the fold line between the front and 4 is parallel to the fold line between the front and right side viewright side viewline 2line 2--4 is a true length line in the right side view4 is a true length line in the right side view

A fold line perpendicular to the true length line gives A fold line perpendicular to the true length line gives the edge view of the oblique surfacethe edge view of the oblique surface

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

Use UCS to rotate about the Z axis and align the X axis with Use UCS to rotate about the Z axis and align the X axis with the edge view of the oblique surfacethe edge view of the oblique surfacePerpendicular projection lines are constructed (ORTHO)Perpendicular projection lines are constructed (ORTHO)Reference planes are used to measure distances along Reference planes are used to measure distances along projection lines (OFFSET and DDOSNAP)projection lines (OFFSET and DDOSNAP)The secondary auxiliary view shows the oblique surface in true The secondary auxiliary view shows the oblique surface in true shapeshape

Another ExampleAnother Example

The top view and front The top view and front view of a surface is view of a surface is shownshownIs an auxiliary view Is an auxiliary view needed to show the needed to show the surface in true shape?surface in true shape?Yes: The surface does Yes: The surface does not appear as an edge not appear as an edge in either viewin either view

ExampleExample

Construct the right Construct the right side view using side view using projection lines and projection lines and reference planesreference planesNote that there are Note that there are no true length lines no true length lines in any of the in any of the principle viewsprinciple views

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

Since the surface does not Since the surface does not appear as an edge in any appear as an edge in any of the principle views the of the principle views the surface is oblique and surface is oblique and requires a secondary requires a secondary auxiliary viewauxiliary viewA line is drawn on the A line is drawn on the surface which is parallel to surface which is parallel to the fold line between the the fold line between the front and right side viewfront and right side viewThis line appears as a true This line appears as a true length line in the right length line in the right side viewside view

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

The true length line is used to get an edge view of the surfaceThe true length line is used to get an edge view of the surfaceA fold line which is perpendicular to a true length line gives A fold line which is perpendicular to a true length line gives a point view of the line in the adjacent viewa point view of the line in the adjacent viewA plane which contains a line that appears as a point will A plane which contains a line that appears as a point will appear as an edgeappear as an edge

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Example: Secondary Auxiliary Example: Secondary Auxiliary ViewView

The secondary The secondary auxiliary view gives auxiliary view gives the true shape of the the true shape of the surfacesurfaceThe secondary The secondary auxiliary view is auxiliary view is constructed by placing constructed by placing a fold line parallel to a fold line parallel to the edge view of the the edge view of the surfacesurface

Example: Secondary Auxiliary Example: Secondary Auxiliary ViewViewFold lines are labeled by the name of Fold lines are labeled by the name of the principle plane or the level of the principle plane or the level of auxiliary viewauxiliary view

Primary auxiliary view (1)Primary auxiliary view (1)Secondary auxiliary view (2)Secondary auxiliary view (2)

Dihedral AngleDihedral AngleA dihedral angle is the angle between two planes. An A dihedral angle is the angle between two planes. An auxiliary view may also be used to determine the auxiliary view may also be used to determine the dihedral angle angle. dihedral angle angle.

To do this, we create a point view of the line of To do this, we create a point view of the line of intersection between the two planes . intersection between the two planes .