Autodesk 235B1-05A761-1301 - AutoCAD MEP 2010, User Manual

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Crosses require 4 trim lengths
To add a trim length, you select valid node points that are displayed in the model and define a distance for
the length. The following illustration shows how trim lengths for a tee fitting would be defined:
A tee has 3 trim lengths: 2 are defined from the center point of the trunk to each end of the trunk legs (1 &
2), and the third is defined from the center of the trunk to the end of the branch leg (3).
Placement Points
For parametric MvParts, the placement point is the insertion point used to place the part in a drawing. You
simply specify a point in your model for the placement point. For parametric fittings, the Auto Layout
advanced option in the Content Builder Options dialog enables automatic part insertion during layout. The
connection 1 position is the insertion position, which can be toggled through.
Model Parameters
Model parameters control the model’s overall shape and size by establishing relationships between defined
parameters. As you add dimensions and constraints to the model, parameters appear under the Model
Parameters folder in the part browser. The Model Parameters dialog provides a central location where you
can view, create, and edit the dimensional parameters of the model. You can define parameters to create
additional model relationships or to enhance drawing schedules later.
It is often more efficient to assign numeric values to dimensions and other feature parameters as you build
the model. When you finalize the geometry, you can edit the model parameters to add calculated values.
An equation assistant is available in the Model Parameters dialog to ensure that the equation you create is
valid and can produce a result. Each parameter in the Model Parameters dialog includes the following:
Name A unique identifier for the parameter. Model parameters are assigned default names, such as D1, D2,
and D3, that can be changed. User-defined parameters must have unique names.
Value The result of evaluating the equation.
Equation The mathematical expression that defines the value of the parameter. Constants, other model
and user-defined parameters, and mathematical operators can be used in an equation. You can use the
Equation Assistant to define the equation.
Description A narrative, user-defined description of the parameter.
NOTE When using a constant value in an equation, be sure to define the constant as a model parameter. You
should verify that the result of the equation is non-zero to avoid undesirable results in your model.
Building Parametric Fittings Using Content Builder | 665