Graphics Programs Reference
In-Depth Information
You use this setting when you want to be able to dimension or align to
the plane but do not want temporary dimensions applied to the plane
when placing the family in a project.
For example, if you have a family that you want to place at its edges but
also want to dimension or align to its center, you would define reference
planes at its edges as strong references and a reference plane at the
center as a weak reference. This is typical for families such as lighting
fixtures or air terminals.
Then the directional parameters:
Left, Right, Front, Back, Top and Bottom
When viewed from the
Ref. Level plan view, front is nearest the bottom of the screen. These
give the user the ability to correctly position an object, and when named
correctly, can also give an indication within the project if the family has
been incorrectly mirrored rather than rotated.
Center (Left/Right), Center (Front/Back) and Center
(Elevation)
These are, in most cases, the best options when choosing
the origin point of the family, which can be used in conjunction with the
Defines Origin parameter, this allows you to set a reference plane as one
of the planes of the origin of a family. Two planes must be set as
defining the origin, and the planes must intersect. The intersection of
the planes in plan view will determine the insertion point of the family.
Reference lines are useful in creating solid geometry when you do not want
to create an infinite plane of reference. Unlike reference planes, reference
lines have a start point and an end point. When you draw a straight
reference line, two planes are formed at the line. One plane is parallel to
the plane in which the line is drawn, and the other is perpendicular to
that plane. This allows you to use the reference line in views parallel and
perpendicular to where it is drawn.
Figure 17.20
shows a reference line that
has been selected to show the four workplanes that can be used, one at each
end, one horizontal, and one vertical. Arced reference lines can be used for
reference but will not create planes.
