Solid Modeling - Engineering Design Graphics - Lecture Slides, Slides of Engineering Drawing and Graphics

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Engineering 22

Solid

Modeling - 1

Learning Goals

• Describe How AutoCAD SOLIDs differ from

WireFrames and Surfaces

• Create AutoCAD “Primitive” Solids
  • Box, Wedge, Cylinder, Sphere, etc.
• Slice and Section 3D Solids
• Use ACAD “Boolean” Operations to create

Solids

• Interfere, Union, Subtract
• Combine Primitives to Make new Solids

Solid Modeling

• Full 3D model (represents actual object)
• Surface, edge, interior features
• Can be cut to show interior detail
• Mass properties may be determined
• Construction techniques
  • Constructive Solid Geometry (CSG)
  • Boundary Representation (B-rep)
• Many display options

Constructive Solid Geometry (CSG)

• Standard “primitive” shapes
• AutoCAD has six primitives:
  • box, wedge, cone, cylinder, torus, sphere
• Primitives are moved into place with 3D

commands to assemble the object

• Primitives are combined with boolean

commands:

• union, subtract, intersection

Invoke Solid Shapes

 Or Command Line

• Box
• Sphere
• Cylinder
• Etc.

Draw Box

Command: _box Specify corner of box or [CEnter] <0,0,0>: Specify corner or [Cube/Length]: 10,12, Specify height: 7

Draw Sphere

 Set Grid Resolution with

IsoLines Command

 Pick Center with Mouse

 Enter Diameter From

KeyBoard

Command: isolines Enter new value for ISOLINES <4>: 24 Command: sphere Current wire frame density: ISOLINES= Specify center of sphere <0,0,0>: Specify radius of sphere or [Diameter]: d Specify diameter: 7.

Draw Circular Cylinder

 Pick with Mouse

• Center
• Radius
• Height

Command: cylinder

Current wire frame density: ISOLINES= Specify center point for base of cylinder or [Elliptical] <0,0,0>: Specify radius for base of cylinder or [Diameter]: Specify height of cylinder or [Center of other end]: Specify second point:

Draw Cone

 Cone Can have Either

Circular or Elliptical Bases

Command: cone Current wire frame density: ISOLINES= Specify center point for base of cone or [Elliptical] <0,0,0>: e Specify axis endpoint of ellipse for base of cone or [Center]: 3.7,4. Specify second axis endpoint of ellipse for base of cone: Specify length of other axis for base of cone: Specify height of cone or [Apex]: 7.

Elliptical, 7.3 High

Circular, 7.3 High

Draw Wedge

 Pick Base Corner and

opposite Diagonal

 Height from KeyBoard

Command: wedge Specify first corner of wedge or [CEnter] <0,0,0>: Specify corner or [Cube/Length]: Specify height: 3.

1st Base Corner

2nd Base Corner

Extrude PolyLine cont.

 Extrude Heptagon made with

Polygon Tool

Command: _-view Enter an option [?/Categorize/lAyer state/Orthographic/Delete/Restore/Save/Ucs/Win dow]: _seiso Regenerating model.

Command: extrude Current wire frame density: ISOLINES= Select objects: 1 found Select objects: Specify height of extrusion or [Path]: 9. Specify angle of taper for extrusion <0>: Command

Extrude Arbitrary PolyLine

 Extrude 2D PolyLine

Command: pline Specify start point: Current line-width is 3. Specify next point or [Arc/Halfwidth/Length/Undo/Width]: h Specify starting half-width <1.7190>:. Specify ending half-width <0.0250>: Specify next point or [Arc/Halfwidth/Length/Undo/Width]: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: Specify next point or [Specify next point or [Arc/Close/Halfwidth/Length/Undo/Width]: c

Revolve Shape

 Revolve

HeptaGon

About Axis

Shown

Command: revolve Current wire frame density: ISOLINES= Select objects: 1 found Specify start point for axis of revolution or define axis by [Object/X (axis)/Y (axis)]: Specify endpoint of axis: Specify angle of revolution <360>: 291

Slice Cylinder w/ Slanted Plane

Command: cylinder Current wire frame density: ISOLINES= Specify center point for base of cylinder or [Elliptical] <0,0,0>: Specify radius for base of cylinder or [Diameter]: Specify height of cylinder or [Center of other end]: 9.

Command: _rectang Specify first corner point or [Chamfer/Elevation/Fillet/Thickness/Width]: Specify other corner point or [Area/Dimensions/Rotation]:

 Make Cylinder

 Make, Twist, and Move Rectangle to

define Plane