Object Basics Continued... Object Basics 1 Overview X Commands T ARC (Command) T CIRCLE (Command) T DONUT (Command) T ELLIPSE (Command) T HELIX (Command) T PLINE (Command) T SPLINE (Command) T BLEND (Command) X System Variables T CIRCLERAD (System Variable) T DONUTID (System Variable) T DONUTOD (System Variable) T PELLIPSE (System Variable) Overview 2 Ellipse Command X The shape of an ellipse is determined by two axes that define its length and width: L the major (longer) axis L the minor (shorter) axis Ellipse Command 3
X Creates a 2D spiral or 3D spring T The following prompts are displayed L Center point of base L Base radius L Diameter (base) L Top radius L Diameter (top) L Helix height L Axis endpoint L Turns L Turn height L Twist O CW Draws the helix in a clockwise direction. O CCW Draws the helix in a counter-clockwise direction 4 X A helix is an open 2D or 3D spiral T You can use a helix as a path along which to sweep an object to create an image L For example, you might sweep a circle along a helix path to create a solid model of a spring T When you create a helix, you can specify the following: L Base radius L Top radius L Height L Number of turns L Turn height L Twist direction 5 X Creates a filled circle or a wide ring T A donut consists of two arc polylines that are joined end-to-end to create a circular shape T The width of the polylines is determined by the specified inside and outside diameters T If you specify an inside diameter of 0, the donut is a filled circle 6
X To create a donut, specify its inside and outside diameters and its center T You can continue creating multiple copies with the same diameter by specifying different center points T To create solid- filled circles, specify an inside diameter of 0 7 X Creates a smooth curve that passes through or near a set of fit points, or that is defined by the vertices in a control frame T SPLINE creates curves called nonuniform rational B-splines (NURBS), referred to as splines for simplicity T Splines are defined either with fit points, or with control vertices T By default, fit points coincide with the spline, while control vertices define a control frame L Control frames provide a convenient method to shape the spline 8 X To display or hide the control vertices and control frame, select or deselect the spline, or use CVSHOW and CVHIDE T The prompts differ, depending on whether you choose Fit or CV (control vertices) as the creation method 9
BLEND Command X Creates a spline in the gap between two selected lines or curves T Select each object near an endpoint T The shape of the resulting spline depends on the specified continuity T The lengths of the selected objects remain unchanged T Valid objects include lines, arcs, elliptical arcs, helixes, open polylines, and open splines BLEND Command 10 FILL Command X Controls the display of filled objects such as hatches, 2D solids, and wide polylines T The following prompts are displayed. L On O Turns on Fill mode L Off O Turns off Fill mode O Only the outlines of objects are displayed and plotted FILL Command 11 CVHIDE Command X Turns off the display of control vertices for all NURBS surfaces and curves T Turns off the CV display for all NURBS objects CVHIDE Command 12
VIEWRES Command X Sets the resolution for objects in the current viewport T VIEWRES controls the appearance of circles, arcs, splines, and arced polylines using short vectors T The greater the number of vectors, the smoother the appearance of the circle or arc VIEWRES Command 13 X CIRCLERAD T Sets the default circle radius X DONUTID T Sets the default for the inside diameter of a donut X DONUTOD T Sets the default for the outside diameter of a donut X FILLMODE T Specifies whether hatches and fills, 2D solids, and wide polylines are filled in X PELLIPSE T Controls the ellipse type created with ELLIPSE L 0 L 1 System Variables Creates a true ellipse object Creates a polyline representation of an ellipse System Variables 14