Circle (Curve)

Functionality

This node generates a Curve object, which represents a circle, or an arc of the circle.

Specifics of curve parametrization: the T parameter is proportional to curve length, and equals to the angle along the circle arc.

Curve domain: defined in node’s inputs, by default from 0 to 2*pi.

Behavior when trying to evaluate curve outside of it’s boundaries: returns corresponding point on the circle.

Optionally, this node can generate a NURBS Curve object. Note that when NURBS mode is enabled, the parametrization of the curve is different from standard parametrization of the circle (defined by the angle).

Inputs

This node has the following inputs:

• Center. A matrix defining the location of the circle. This may be used to move, scale or rotate the curve. By default, the center of matrix is at the origin, and the circle is laying in the XOY plane.

Generator-> NGon, Matrix-> Matrix In

• Radius. Circle radius. The default value is 1.0.

• T Min. Minimum value of the curve parameter. In Generic mode, the parameter is the angle on the arc. The default value is 0.0.

• T Max. Maximum value of the curve parameter. In Generic mode, the parameter is the angle on the arc. The default value is 2*pi (radians).

• NPoints. This input is available only when Mode parameter is set to NURBS. Defines the number of corners in curve’s control polygon. The minimum value is 3. The default value is 4.

Parameters

This node has the following parameters:

• Mode. This defines the type of the curve to be generated. The available options are:

  • Generic. Create a generic Circle Curve object with standard angle-based parametrization.

  • NURBS. Create a NURBS Curve object.

  The default mode is Generic.

• Angle Units. The units in which values of T Min, T Max inputs are measured. The available options are:

  • Rad. Radians (2*pi is full circle).

  • Deg. Degrees (360 is full circle).

  • Uni. Unit circles (1.0 is full circle).

  The default value is Rad.

Outputs

This node has one output:

• Curve. The circle (or arc) curve.

Examples of usage

Simple use:

• Viz-> Viewer Draw Curve

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Use together with Extrude node to create a surface:

• Surfaces-> Extrude Curve Along Vector

• Viz-> Viewer Draw Curve

• Viz-> Viewer Draw Surface

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Example of NURBS mode usage:

• Curves->Curve NURBS-> Deconstruct Curve

• Viz-> Viewer Draw

• Viz-> Viewer Draw Curve