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Introduction to the Alphabet of Lines
Object line- Heavy solid line that shows visible edges or contour of an object.
Hidden Line- Broken medium weight line that shows non visible features.
Hole through material beyond visible front surface.
Center Line- Fine broken line with long and short dashes. Shows middle axis of parts.
Extension Line- Fine solid line that shows where dimensions are being taken from.
Dimension Line- Fine solid line with arrow heads on both ends. Shows the length and direction of dimensions, typically used with extension lines.
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Cutting Plane Line- Heavy line with short and long dashes, ended with arrowheads. Shows internal features that cannot be seen from any other view. Arrowheads point in direction that section view should be viewed.
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