Sketch > Spline and Polyline

In the ribbon, as well as in the automenu of the Sketch command, options of spline creation are grouped into a drop-down list. The presence of the drop-down list is indicated by the black triangle near an icon of an option displayed, when the list is folded. In order to unfold the list, either click a triangle in the ribbon, or click and hold on an icon of an option displayed, when the list is folded. This icon corresponds to an option used last in the current CAD session. When the Sketch command is launched, any option can be called via keyboard without unfolding the list.

Types of Spline

Following types are available:

The spline goes through given control points.

A polygonal line goes through control points, and the spline (NURBS) is based on such line.

A closed spline goes through given control points.

A closed spline (NURBS) based on polygonal line, where latter goes through control points.

A first degree spline.

Visually, when creating a polyline, we get consecutive line segments. However, the interrelations of these segments is different than if we would draw line segments in a continuous sketching mode or parametric segments (with constraint). In contrast to the line option, a broken polyline is a single object.

For example, parts of a polyline cannot be rounded together, and when a segment is deleted, the deleted part will consist of a set of segments. You can create an offset curve to the polyline.

A closed first degree spline.

While creating and editing a spline, you can change its type at any moment.

 

The spline drawing command functional in construction lines and in a sketch is practically identical. But there are some minor differences.

•Object snapping doesn't recognize control points of the construction spline.

•A node can be snapped to construction spline, with specifying a relative position along the spline.

•The parameters dialog of a construction spline parameters is different from the one of a sketch spline.

Creating a Spline

Choose one of the aforementioned spline types. Specify the location of control points with . The points can be bound to 2D nodes. The location of the points can be defined using object snapping. Upon specifying a first (second for closed splines) control point, the dynamic preview of the spline appears on the screen. The last point of the spline follows the cursor, so the preview changes accordingly. When creating a spline by polyline, a preview of a polyline is shown along with a preview of a spline.

 

Coordinates and other parameters of the specified points, as well as geometrical parameters of the spline as whole, are shown in the parameters window (see the Geometrical Parameters of Spline section).

Specify control points, their parameters, parameters of spline as whole and then finish the spline creation using either the (<Ctrl>+<Enter>) option, or double click .

Automenu options

Initially, upon calling any of the sketch spline creation commands, the full set of the Sketch command's options is available in the automenu.

Upon defining two control points, the set of automenu options changes to following:

Finishes the creation of a current spline and starts creation of another one.

Invokes the spline's parameters dialog

Right-click or activating this option option, brings up the Right button action dialog, unless the Don't Show this dialog in future option was enabled earlier in the current session. Upon selecting the Continue operation action in the dialog, adding control points to the end of the spline stops, but you can still can add intermediate ones by clicking at the desired location on the spline or edit any of the spline's parameters. In order to resume adding points to the end of the spline, select the last point in the list of points displayed in the parameters window and click the Add after button.

See also:

•Spline Analysis

•Main Concepts of 2D Spline

•2D Spline Point Controls

•Geometrical Parameters of 2D Spline

•Graphic Line Parameters

•Edit Splines

•Right button action

•Spline based on 3D Nodes