- [Instructor] Orientation tolerances control
the angle of a given feature relative to a given datum.
Two special cases of angle features exist.
When the desired angle is either zero
and the feature is parallel to the datum,
or 90 degrees and the feature is perpendicular to the datum.
The perpendicularity control constrains how far
an axis or a plane can deviate from a right angle
with regards to a datum reference plane or a line.
Perpendicularity is defined as a distance, not as an angle.
So it describes the set of parallel lines or planes
perpendicular to the datum, which lie on either side
of the geometry being controlled.
These lines or planes are separated by
a distance specified by the perpendicularity control.
Every point of the geometry being controlled
must lie between these parallel lines or planes.
The parallelism control constrains how far
an axis or a plane can deviate from parallel
with regards to a datum reference plane or line.
Parallelism is defined as a distance,
so it describes the set of parallel lines
or planes mutually parallel to the datum.
These parallel lines or planes lie on either side
of the geometry being controlled,
separated by a distance specified
by the parallelism control.
Every point of the geometry being controlled
must lie between these parallel lines or planes.
The angularity control constrains how far
an axis or plane can deviate from being at
a particular angle with reference to a datum plane or line.
Although the name might suggest otherwise,
angularity is defined as a distance, not as an angle.
For a given desired angle dimension,
angularity describes a set of parallel planes or lines
which are oriented at the desired angle
relative to our given datum.
These parallel lines or planes lie on either side
of the geometry being controlled
and are separated by a distance specified by
the angularity control.
Every point of the geometry being controlled
must lie between these parallel lines or planes.