Autodesk AUTOSKETCH 8, Руководство пользователя

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Using Extrusion Tools
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Since objects appear to get smaller as they move further away,
3D Perspective Extrusion creates a scaled copy of the selection set. Like
3D Parallel Extrusion, you place the copy anywhere in the drawing and
AutoSketch connects the corresponding edges using lines or polygons.
Both commands require you to enter points that define the distance and
direction AutoSketch uses to perform the 3D effect. 3D Parallel Extrusion
requires you to enter two points—a “from” point and a “to” point. These
points can be located at any point in the drawing and do not have to be on
the actual entity. This is helpful if you want to define the distance and direc-
tion based on known points in the drawing. For instance, in an isometric
drawing of a chair, you might want to extrude an ellipse to create a rail for
the legs.
3D Perspective Extrusion requires you to enter a “to” point only. However,
this command has one additional control. When you click the
3D Perspective Extrusion button on the 3D Effects toolbar, the edit bar
displays the Depth text box. The Depth value is a percentage that determines
how far toward the vanishing point (represented by the pointer) the extru-
sion extends. This value cannot be less than 1%, which creates very little
extrusion, or greater than 99%. For example, if you set the Depth value to
60%, then move the pointer ten units, AutoSketch extrudes the entity six
units, or 60% of the distance to the vanishing point, from the original.
CAUTION
Extruding text entities that contain many characters may create
large numbers of entities which, in turn, requires a large amount of memory to
create a view. It is not recommended that you extrude text entities that contain
more than a few characters.
Parallel extrusion Perspective extrusion