Autodesk 00308-011408-9F30A User Guide - Page 197

s 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. Parallel extrusion Perspective extrusion 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 direction 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 extrusion 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. Using Extrusion Tools | 187