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🔧 ORTHOGRAPHIC PROJECTION AND CAD, :Relationship between the drawing size…
🔧 ORTHOGRAPHIC PROJECTION AND CAD
ORTHOGRAPHIC PROJECTION
Representation of 3D objects on a 2D plane
Projection lines are perpendicular to the projection plane
Shows the shape and dimensions of an object
Used in technical drawing
VIEWS
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Front View
Height
Width
Main view
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Top View
Width
Depth
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Side View
Height
Depth
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Purpose
Represent an object completely using different views
FIRST-ANGLE AND THIRD-ANGLE PROJECTION
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First-Angle Projection
Object is between the observer and the projection plane
Views are placed opposite to the direction of observation
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Third-Angle Projection
Projection plane is between the observer and the object
Views are placed in the same direction as the observation
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Difference
The position of the views changes
Each method has a standardized symbol
SCALE
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Full Scale
1:1
Same size as the real object
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Reduction Scale
1:n
Drawing is smaller than the real object
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Enlargement Scale
n:1
Drawing is larger than the real object
TYPES OF LINES
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Visible Lines
Show visible edges and contours
Continuous lines
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Hidden Lines
Show edges or elements that cannot be seen
Dashed lines
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Center Lines
Show centers and axes
Indicate symmetry
Used for holes and circular features
DIMENSIONNING
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Dimension Lines
Show the distance being measured
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Extension Lines
Indicate the points between which the measurement is taken
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Arrows
Mark the ends of a dimension
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Dimension Values
Show the measurement
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Requirements
Clear
Precise
No unnecessary dimensions
:Relationship between the drawing size and the real object size
:Shows the dimensions of an object