02_Gambar Teknik - Geometri
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Transcript of 02_Gambar Teknik - Geometri
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 1
CHAPTER 2CHAPTER 2:
GEOMETRY
AE-1022: AIRCRAFT DRAWING
Outline
Engineering geometry
Coordinate spaces Coordinate spaces
Geometric elements
Points, lines, surfaces & arcs
Conic curves
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 2
Engineering Geometry
Geometric construction: Act of constructing a geometry, especially using hand toolsespecially using hand tools
Engineering geometry: Basic geometric elements and forms
e.g., dividing a line
Engineering geometry: Basic geometric elements and forms used in engineering design
Points, Lines, Surfaces, and Solids
Coordinate Spaces
2-D Cartesian coordinate system
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 3
Coordinate Spaces (con’t)
3-D coordinate system
Coordinate Spaces (con’t)
Display of coordinate axis in a multiview drawing
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 4
Coordinate Spaces (con’t)
Right-hand rule: Used to determine the Used to determine the positive direction of the axes
Note: counter clockwise is positive – default positive rotation of CAD
Coordinate Spaces (con’t)
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 5
Coordinate Spaces (con’t)
Polar coordinates(distance in X-Y plane and angle
Cylindrical coordinates(distance and angle in X-Y plane (distance in X-Y plane and angle
from X axis)(distance and angle in X-Y plane and distance in Z)
Coordinate Spaces (con’t)
Spherical coordinates(angle in two planes and one
Absolute coordinates(referenced to fixed origin)(angle in two planes and one
distance parameter)
( g )
Relative coordinates(referenced to previous point)
World coordinates (referenced back to origin)
Local coordinates(moving system positioned (moving system positioned anywhere in space)
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 6
Coordinate Spaces (con’t)
World Coordinates
User Coordiates
Geometric Elements
Manual drafting AutoCAD
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 7
Points, Lines, Surfaces, and Arcs
Point: Theoretical location that has neither width, height, nor depth and describes an exact location in spacedepth and describes an exact location in space
Points, Lines, Surfaces, and Arcs (con’t)
Line: Geometric primitive that has length and that has length and direction but not thickness May be straight, curved, or a
combination
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 8
Points, Lines, Surfaces, and Arcs (con’t)
Tangencies: Exists when a straight line is in contact with a curve at a single point; that is a line is tangent to a circle if it curve at a single point; that is, a line is tangent to a circle if it touches the circle at one and only one point
Points, Lines, Surfaces, and Arcs (con’t)
Circles: Single curved surface primitive, all points of which are equidistant from one point, the center
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 9
Points, Lines, Surfaces, and Arcs (con’t)
• The elements of a circle are as follows (outlined in previous slide):
Center
Circumference
Radius
Chord
Diameter
Minor arc
Major arc
Central angle
Sector
Quadrant
S t
( p )
Secant
Arc
Semicircle
Segment
Tangent
• The slides that follow provide examples of manualdrafting points, lines, surfaces, and mostly, arcs
Points, Lines, Surfaces, and Arcs (con’t)
Constructing arcs tangent to two
lines
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 10
Points, Lines, Surfaces, and Arcs (con’t)
Constructing an arc tangent to a line and another arc
Points, Lines, Circles, and Arcs (con’t)
Constructing an arc tangent to two given arcs or circles
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 11
Points, Lines, Circles, and Arcs (con’t)
Constructing an arc tangent to two given
arcs
Points, Lines, Circles, and Arcs (con’t)
Constructing an arc tangent to a given arc
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 12
Points, Lines, Circles, and Arcs (con’t)
Constructing lines tangent to two circles or arcs using a arcs, using a
straightedge (a trial and error
method)
Conic Curves
Parabola: Curve created when a plane intersects a right circular cone parallel to the side (elements) of the conecircular cone parallel to the side (elements) of the cone
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 13
Conic Curves (con’t)
Parallelogram Parallelogram Method of
Drawing Parabolas
Engineering Applications of Parabolas
Conic Curves (con’t)
Hyperbola: Curve of the intersection created when a plane intersects a right circular cone and makes a smaller angle intersects a right circular cone and makes a smaller angle with the axis than do the elements
AE‐1022: AIRCRAFT DRAWING 10/27/2009
CHAPTER 2: GEOMETRY 14
Conic Curves (con’t)
Ellipse: Single-curved-surface primitive – created surface primitive created when a plan passes through a right circular cone at an angle to the axis that is greater than the angle between the axis and the sides (a circle when viewed sides (a circle when viewed at an angle appears as an ellipse)
Conic Curves (con’t)
Constructing a Foci Ellipse