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selected objects or subobjects. The extracted edges form a duplicate
wireframe composed of 2D objects such as lines, circles, and 3D polylines.
■ Enter 3D coordinates that define the X, Y, and Z location of the object.
■ Set the default work plane (the XY plane of the UCS) on which to draw the
object.
■ Move or copy the object to its proper 3D location after you create it.
Wireframe modeling is a skill that requires practice and experience. The best
way to learn how to create wireframe models is to begin with simple models
before attempting models that are more complex.
Tips for Working with Wireframe Models
Creating 3D wireframe models can be more difficult and time-consuming
than creating their 2D views. Here are some tips that will help you work more
effectively:
■ Plan and organize your model so that you can turn off layers to reduce the
visual complexity of the model. Color can help you differentiate between
objects in various views.
■ Create construction geometry to define the basic envelope of the model.
■ Use multiple views, especially isometric views, to make visualizing the
model and selecting objects easier.
■ Become adept at manipulating the UCS in 3D. The XY plane of the current
UCS operates as a work plane to orient planar objects such as circles and
arcs. The UCS also determines the plane of operation for trimming and
extending, offsetting, and rotating objects.
■ Use object snaps and grid snap carefully to ensure the precision of your
model.
■ Use coordinate filters to drop perpendiculars and easily locate points in
3D based on the location of points on other objects.
To drop a perpendicular line from a 3D point down to the XY plane
1 Click Home tab ➤ Draw panel ➤ Line.
2 Use an object snap to specify a point on an object that is not on the XY
plane of the UCS.
This location defines the first point of the line.
1154 | Chapter 24 Create 3D Models