Solids1 PDF

8/11/2019 Solids1 PDF

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Regular Polyhedra

A polyhedron with faces that are equal and regular

TetrahedronCube or hexahedron Octahedron

DodecahedronIcosahedron
http://upload.wikimedia.org/wikipedia/commons/7/70/Tetrahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/4/48/Hexahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/1/14/Octahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/e/e2/Icosahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/7/73/Dodecahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/7/70/Tetrahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/4/48/Hexahedron.gifhttp://upload.wikimedia.org/wikipedia/commons/1/14/Octahedron.gif


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OBLIQUE PRISM

Bases are not regular

Axis is not perpendicular to the bases

Prism


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Irregular PolyhedraPyramid Polyhedron with n-sided polygonal base connected to a point

(called APEX) by n triangular faces

http://mathworld.wolfram.com/Pyramid.html

axis

Slant Edges Face
http://mathworld.wolfram.com/Pyramid.htmlhttp://mathworld.wolfram.com/Pyramid.html


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RIGHT PYRAMID

Axis connecting the centre of the base to the apex is

perpendicular to the base

Pyramid

OBLIQUE PYRAMID

Axis connecting the centre of the base to the apex is

inclined to the base


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Solids of revolution

Cylinder Cone Sphere

The solids generated by the revolution of certain plane figures

about a fixed line (axis) are called solids of revolution


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Frustums of solids

When the solids like pyramids or cones are cut by planes which are

parallel to the base (thus removing the top portion), the cut solid

are called the FRUSTUM of those solids.

When the solids like pyramids or cones are cut by planes which are

not parallel to the base (thus removing the top portion), the cutsolid are called the truncated solids.

Truncated coneFrustum of a cone


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Projections of solids (simple positions)

A solid in simple position may have its axis perpendicular to

one of the reference plane or parallel to both. When the axis is perpendicular to one reference plane, it is

parallel to the other.

When the axis of a solid is

perpendicular to a plane, its

base will be parallel to that

plane


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Axis perpendicular to one ref. plane

When axis is perpendicular to HP or ground:

The TV will show the true shape and size of base. The TV

is drawn first and then the FV is projected from it.

Draw the projections of a

pentagonal pyramid, base 40 mmedge and axis 60 mm long,

having its base on the ground

and an edge of the base parallel

to VP.


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When axis is perpendicular to PP (OR parallel to HP

and VP): The SV (LSV or RSV) will show the true shape and size

of base. The SV is drawn first and then the TV and FV areprojected from it.

Axis perpendicular to one ref. plane

A triangular prism, base 40 mm

side and height 60 mm is restingon the ground on one of its

rectangular faces with the axis

parallel to VP. Draw its

projections.


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Exercise A

(Projection of solids in simple position)

1 unit = 4 grid spacing = 100mm.

Use point for locating the center with PDMODE: 2 andPDSIZE: 0.15.

Draw a polygon by edge method and locate the center of thepolygon / circle.

Show the axis by a centerline

( ).


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Concept of transfer of points from one

view to the other view

The transfer of points from one view to another view

is frequently required to locate key points from cutpoints

Section of solids

Intersection of surfaces


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Announcements

Tutorial class will be conducted tomorrow

(18.03.09) on PROJECTION OF SOLIDS

Section 3 (INSTRUCTOR Ms. Meghana Charde)go to Section 2 (Room 2215) and 10 (Room 2213).

2008A1PS332P 2008A4PS230P (Section 2)

2008A4PS292P 2008D2TS885P (Section 10)

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