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Create 3D Objects | 297
Warning! Because each modeling type uses a different method for construct-
ing 3D models and editing methods vary in their effect on the different model
types, it is recommended that you not mix modeling methods. Limited conver-
sion between model types is available from solids to surfaces and from surfaces
to wireframes; however, you cannot convert from wireframes to surfaces or from
surfaces to solids.
Add Extruded Thickness to Objects
Thickness is a property of objects that simulates surfaces in AutoCAD.
The thickness of an object is the distance that object is extruded, or extended,
above or below its location in space. Positive thickness extrudes upward in
the positive Z direction; negative thickness extrudes downward (negative Z).
Zero (0) thickness means no extrusion. The Z direction is determined by the
orientation of the UCS at the time the object was created. Objects with thick-
ness can be shaded and can hide other objects behind them.
Thickness changes the appearance of circles, lines, polylines (including
spline-fit polylines, rectangles, polygons, boundaries, and donuts), arcs, 2D
solids, and points. Modifying the thickness of other types of objects does not
affect their appearance.
You can set the thickness for new objects you create in AutoCAD with the
THICKNESS system variable. Change the thickness of an existing object using
the
PROPERTIES command. AutoCAD applies the extrusion uniformly on an
object: a single object cannot have different thicknesses for its various points.
You may need to change the 3D viewpoint to see the effect of thickness on
an object.
2D objects elevation changed thickness added