17-01-2013, 04:04 PM
Parametric Modeling with UGS NX 6
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Parametric Modeling Fundamentals
♦ Create Simple Extruded Solid Models
♦ Understand the Basic Parametric
Modeling Procedure
♦ Create 2-D Sketches
♦ Understand the "Shape before Size"
Approach
♦ Use the Dynamic Viewing Commands
♦ Create and Edit Parametric Dimensions
Introduction
The feature-based parametric modeling technique enables the designer to incorporate
the original design intent into the construction of the model. The word parametric means
the geometric definitions of the design, such as dimensions, can be varied at any time in
the design process. Parametric modeling is accomplished by identifying and creating the
key features of the design with the aid of computer software. The design variables,
described in the sketches and described as parametric relations, can then be used to
quickly modify/update the design.
In UGS NX, the parametric part modeling process involves the following steps:
1. Set up Units and Part name.
2. Determine the type of the base feature, the first solid feature, of the design.
Note that Extrude, Revolve, or Sweep operations are the most common
types of base features.
3. Create a rough two-dimensional sketch of the basic shape of the base feature
of the design.
4. Apply/modify constraints and dimensions to the two-dimensional sketch.
5. Transform the parametric two-dimensional sketch into a 3D solid.
6. Add additional parametric features by identifying feature relations and
complete the design.
7. Perform analyses/simulations, such as finite element analysis (FEA) or cutter
path generation (CNC), on the computer model and refine the design as
needed.
8. Document the design by creating the desired 2D/3D drawings.
The approach of creating two-dimensional sketches of the three-dimensional features is
an effective way to construct solid models. Many designs are in fact the same shape in
one direction. Computer input and output devices we use today are largely twodimensional
in nature, which makes this modeling technique quite practical. This method
also conforms to the design process that helps the designer with conceptual design along
with the capability to capture the design intent. Most engineers and designers can relate
to the experience of making rough sketches on restaurant napkins to convey conceptual
design ideas. UGS NX provides many powerful modeling and design-tools, and there are
many different approaches to accomplishing modeling tasks. The basic principle of
feature-based modeling is to build models by adding simple features one at a time. In
this chapter, the general parametric part modeling procedure is illustrated; a very simple
solid model with extruded features is used to introduce the UGS NX user interface.