Convert to NURBS (Surfaces)

Modify Surface Convert to NURBS

The Convert Surface to NURBS command enables you to convert one or more surfaces into NURBS entities.

After selecting the surfaces to be modified (the Surfaces item in the selection list will turn to green), three different conversion methods can be selected in the Fix drop-down list: Tolerance, Parameters and Advanced.

Tolerance
Performs conversion after enabling you to set the tolerance value you want to reach and after specifying, in the Max. Control Pts U and Max. Control Pts V boxes, the maximum number of control points for the resulting surface along the two parametric directions.
Unless you require a Specialized conversion by selecting the Specialized conversion check box under More Options, the program will create a NURBS surface which is cubic in both the "U" and the "V" parametric directions.

Parameters
Performs conversion after enabling you to set the parameter values of the NURBS you want to obtain:

Cont. U	Enables you to define the degree of continuity of the resulting surface along its U parametric direction.
Cont. V	Enables you to define the degree of continuity of the resulting surface along its V parametric direction.

Arcs U	Enables you to define the number of arcs of the resulting surface along its U parametric direction.
Arcs V	Enables you to define the number of arcs of the resulting surface along its V parametric direction.

Deg. U	Enables you to define the degree of the resulting surface along its U parametric direction.
Deg. V	Enables you to define the degree of the resulting surface along its V parametric direction.

Using this method you can create NURBS of higher degree, but you will have to try by setting different values until you obtain the desired Achieved tolerance. The Farthest Point check box enables you to display the point that is farthest away from the surface.

Advanced
Performs conversion after enabling you to set the Boundary continuity order and the Continuity order for the internal areas of the resulting surface. This method will even enable you to force the creation of high knot continuity NURBS (internal knots with multiplicity 1. As multiplicity for a NURBS is the difference between its degree and the value of its continuity, the continuity value for NURBS with multiplicity 1 is maximum). See "Using the Advanced conversion options" for further details.

The Show Control Points check box enables you to display a preview of the resulting surface control points at any time when the command is active.

When the box is checked, the control points are displayed.
When the box is cleared, the control points are not displayed.

The Show Arc Joints check box enables you to display a preview of the arc joints that you will obtain on the resulting NURBS entity. The option is active only after you have selected the Preview ( ) button.

When the box is checked, the arc joints are displayed.
When the box is cleared, the arc joints are not displayed.

The type of the resulting surfaces can be chosen through the Output type drop-down list under More Options: you can obtain a single NURBS surface or a set of single-patch surfaces (which can also be of the Bezier type). For details, see the description of the Output type drop-down list in "Using additional conversion options (More Options)".

Appropriate yellow warnings are displayed on the model before applying the command, just by using the appropriate warning button ( ), so as to enable you to do the necessary adjustments.

Associative Mode
The surfaces created using this command can be associative: associative surfaces are Skins, that is open solids, retaining a link to the base entities, so that if you modify the base entities the surfaces will be modified accordingly; they have a history and are displayed in the Model Structure. See "Associative Surfaces (Skins) for details.

Tips and Tricks

Related Topics