Orthographic Projection

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Orthographic Projection
Sectional Views
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Section Views

• When a part has a lot of interior details, hidden
  lines can make the part hard to understand and
  dimension. To see the interior of these parts,
  we cut some of the part away. This allows for
  details to be seen clearly, as well as, giving us
  alternative locations to properly dimension the
  part.

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Sectional Views

• Types of Sectional Views
• Half
• Full
• Offset
• Removed
• Revolved
• Broken-out
• Aligned

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Half Section
Notice how the cutting plane line runs through
the center of the part and there is no arrow
head.

• In a half section, one quarter of the part is cut
  away. This is done with symmetrical parts where
  you would like to show the outside, as well as,
  the inside details.

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Full Section
A full section is a view that shows what the
object looks like if it were cut in half.
A cutting plane line is used to indicate how the
front view was cut. It is also labeled in case
another section is necessary. The arrows should
point in the line of sight as you are looking
straight on at the section.
Section lines called Hatch lines are used to show
where the part is solid. This helps to see the
detail that would be normally blocked and only
shown as hidden lines.
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Offset Section
Interior features not in line with each other can
be shown in an offset section view. Note how the
cutting plane line changes and follows the center
of each feature.
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Revolved Sections

• Used when an object has a constant shape
  throughout the length that cannot be illustrated
  in an external view.
• The section is revolved 90 degrees. It may be
  represented one of two ways, either broken away
  or not.

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Not Broken Away Revolved Section
Section is revolved 90 degrees
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Broken Away Revolved Section
Section is revolved 90 degrees and broken away
from part
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Broken-out Section Views

• A small portion of an object may be broken away
  to clarify an interior surface or feature. No
  cutting plane line is used.

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Broken-out Section View
Section exposes the interior surfaces
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Removed Sections

• A cutting plane is placed through the part where
  the section is taken. The removed sections are
  not aligned with the view. Placement is in the
  surrounding area.

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Removed Sections
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Aligned Section Views

• A true projection of a part with inclined ribs,
  spokes, and arms will be foreshortened. An
  aligned section view is recommended to acquire
  accurate dimensions of the part. The cutting
  plane is bent at an angle as it passes through
  the object. The section view is then projected
  90 degrees from the cutting plane and is in
  alignment to the original view.

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Aligned Section Views